x86/asm/entry: Move entry_64.S and entry_32.S to arch/x86/entry/

Create a new directory hierarchy for the low level x86 entry code:

arch/x86/entry/*

This will host all the low level glue that is currently scattered
all across arch/x86/.

Start with entry_64.S and entry_32.S.

Cc: Borislav Petkov <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: Denys Vlasenko <[e-mail]>
Cc: Brian Gerst <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/Kbuild

···
+
+obj-y += entry/
+
 obj-$(CONFIG_KVM) += kvm/
 
 # Xen paravirtualization support

arch/x86/entry/Makefile

···
+#
+# Makefile for the x86 low level entry code
+#
+obj-y			:= entry_$(BITS).o

arch/x86/kernel/Makefile

···
 
 CFLAGS_irq.o := -I$(src)/../include/asm/trace
 
-obj-y			:= process_$(BITS).o signal.o entry_$(BITS).o
+obj-y			:= process_$(BITS).o signal.o
 obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o ldt.o dumpstack.o nmi.o
 obj-y			+= setup.o x86_init.o i8259.o irqinit.o jump_label.o