docs: admin-guide: add kdump documentation into it

The Kdump documentation describes procedures with admins use
in order to solve issues on their systems.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/admin-guide/bug-hunting.rst

···
     run a null modem to a second machine and capture the output there
     using your favourite communication program.  Minicom works well.
 
-(3) Use Kdump (see Documentation/kdump/kdump.rst),
+(3) Use Kdump (see Documentation/admin-guide/kdump/kdump.rst),
     extract the kernel ring buffer from old memory with using dmesg
-    gdbmacro in Documentation/kdump/gdbmacros.txt.
+    gdbmacro in Documentation/admin-guide/kdump/gdbmacros.txt.
 
 Finding the bug's location
 --------------------------

Documentation/admin-guide/index.rst

···
    ramoops
    dynamic-debug-howto
    init
+   kdump/index
    perf/index
 
 This is the beginning of a section with information of interest to

Documentation/admin-guide/kernel-parameters.txt

···
 			[KNL, x86_64] select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
-			See Documentation/kdump/kdump.rst for further details.
+			See Documentation/admin-guide/kdump/kdump.rst for further details.
 
 	crashkernel=range1:size1[,range2:size2,...][@offset]
 			[KNL] Same as above, but depends on the memory
 			in the running system. The syntax of range is
 			start-[end] where start and end are both
 			a memory unit (amount[KMG]). See also
-			Documentation/kdump/kdump.rst for an example.
+			Documentation/admin-guide/kdump/kdump.rst for an example.
 
 	crashkernel=size[KMG],high
 			[KNL, x86_64] range could be above 4G. Allow kernel
···
 			Specifies physical address of start of kernel core
 			image elf header and optionally the size. Generally
 			kexec loader will pass this option to capture kernel.
-			See Documentation/kdump/kdump.rst for details.
+			See Documentation/admin-guide/kdump/kdump.rst for details.
 
 	enable_mtrr_cleanup [X86]
 			The kernel tries to adjust MTRR layout from continuous

Documentation/kdump/index.rst Documentation/admin-guide/kdump/index.rst

···
-:orphan:
 
 ================================================================
 Documentation for Kdump - The kexec-based Crash Dumping Solution

Documentation/powerpc/firmware-assisted-dump.txt

···
          the default calculated size. Use this option if default
          boot memory size is not sufficient for second kernel to
          boot successfully. For syntax of crashkernel= parameter,
-         refer to Documentation/kdump/kdump.rst. If any offset is
+         refer to Documentation/admin-guide/kdump/kdump.rst. If any offset is
          provided in crashkernel= parameter, it will be ignored
          as fadump uses a predefined offset to reserve memory
          for boot memory dump preservation in case of a crash.

Documentation/translations/zh_CN/oops-tracing.txt

···
 （2）用串口终端启动（请参看Documentation/admin-guide/serial-console.rst），运行一个null
 modem到另一台机器并用你喜欢的通讯工具获取输出。Minicom工作地很好。
 
-（3）使用Kdump（请参看Documentation/kdump/kdump.rst），
-使用在Documentation/kdump/gdbmacros.txt中定义的dmesg gdb宏，从旧的内存中提取内核
+（3）使用Kdump（请参看Documentation/admin-guide/kdump/kdump.rst），
+使用在Documentation/admin-guide/kdump/gdbmacros.txt中定义的dmesg gdb宏，从旧的内存中提取内核
 环形缓冲区。
 
 完整信息

MAINTAINERS

···
 L:	[e-mail]
 W:	http://lse.sourceforge.net/kdump/
 S:	Maintained
-F:	Documentation/kdump/
+F:	Documentation/admin-guide/kdump/
 
 KEENE FM RADIO TRANSMITTER DRIVER
 M:	Hans Verkuil <[e-mail]>

arch/arm/Kconfig

···
 	  kdump/kexec. The crash dump kernel must be compiled to a
 	  memory address not used by the main kernel
 
-	  For more details see Documentation/kdump/kdump.rst
+	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
 config AUTO_ZRELADDR
 	bool "Auto calculation of the decompressed kernel image address"

arch/arm64/Kconfig

···
 	  reserved region and then later executed after a crash by
 	  kdump/kexec.
 
-	  For more details see Documentation/kdump/kdump.rst
+	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
 config XEN_DOM0
 	def_bool y

arch/sh/Kconfig

···
 	  to a memory address not used by the main kernel using
 	  PHYSICAL_START.
 
-	  For more details see Documentation/kdump/kdump.rst
+	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
 config KEXEC_JUMP
 	bool "kexec jump (EXPERIMENTAL)"

arch/x86/Kconfig

···
 	  to a memory address not used by the main kernel or BIOS using
 	  PHYSICAL_START, or it must be built as a relocatable image
 	  (CONFIG_RELOCATABLE=y).
-	  For more details see Documentation/kdump/kdump.rst
+	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
 config KEXEC_JUMP
 	bool "kexec jump"
···
 	  the reserved region.  In other words, it can be set based on
 	  the "X" value as specified in the "crashkernel=YM@XM"
 	  command line boot parameter passed to the panic-ed
-	  kernel. Please take a look at Documentation/kdump/kdump.rst
+	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
 	  for more details about crash dumps.
 
 	  Usage of bzImage for capturing the crash dump is recommended as