x86: mention ACPI in top-level Kconfig menu

Impact: clarify menuconfig text

Mention ACPI in the top-level menu to give a clue as to where
it lives. This matches what ia64 does.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig

@@ -1494,7 +1494,7 @@ config HAVE_ARCH_EARLY_PFN_TO_NID
 	def_bool X86_64
 	depends on NUMA
 
-menu "Power management options"
+menu "Power management and ACPI options"
 	depends on !X86_VOYAGER
 
 config ARCH_HIBERNATION_HEADER