Reflect this dependency in Kconfig, to prevent build failures.

Shorten the config description as suggested by Borislav Petkov.

Finding a suitable memory area to store the modified table(s) has been
taken over from arch/x86/kernel/setup.c and makes use of max_low_pfn_mapped:
memblock_find_in_range(0, max_low_pfn_mapped,...)
This one is X86 specific. It may not be hard to extend this functionality
for other ACPI aware architectures if there is need for.

For now make this feature only available for X86 to avoid build failures on
IA64, compare with:
https://bugzilla.kernel.org/show_bug.cgi?id=54091Signed-off-by: NThomas Renninger <trenn@suse.de>
Link: http://lkml.kernel.org/r/1361538742-67599-3-git-send-email-trenn@suse.deSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>