x86, pat: Generalize the use of page flag PG_uncached

Only IA64 was using PG_uncached as of now. We now intend to use this bit
in x86 as well, to keep track of memory type of those addresses that
have page struct for them. So, generalize the use of that bit across
ia64 and x86.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 170042b..e624611 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -112,6 +112,10 @@
 	bool
 	select GENERIC_ALLOCATOR
 
+config ARCH_USES_PG_UNCACHED
+	def_bool y
+	depends on IA64_UNCACHED_ALLOCATOR
+
 config AUDIT_ARCH
 	bool
 	default y