x86/kasan: Move KASAN_SHADOW_OFFSET to the arch Kconfig

KASAN_SHADOW_OFFSET is purely arch specific setting,
so it should be in arch's Kconfig file.

Signed-off-by: Andrey Ryabinin <[e-mail]>
Cc: Alexander Popov <[e-mail]>
Cc: Alexander Potapenko <[e-mail]>
Cc: Andrey Konovalov <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Paul Bolle <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/Kconfig

···
 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	def_bool y
 
+config KASAN_SHADOW_OFFSET
+	hex
+	depends on KASAN
+	default 0xdffffc0000000000
+
 config HAVE_INTEL_TXT
 	def_bool y
 	depends on INTEL_IOMMU && ACPI

lib/Kconfig.kasan

···
 	  For better error detection enable CONFIG_STACKTRACE,
 	  and add slub_debug=U to boot cmdline.
 
-config KASAN_SHADOW_OFFSET
-	hex
-	default 0xdffffc0000000000 if X86_64
-
 choice
 	prompt "Instrumentation type"
 	depends on KASAN