x86: make mm/gup.c more virtualization friendly

Since pte_flags() is much cheaper than pte_val() in some virtualized
environments (namely, Xen), use the former whereever possible.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: "Nick Piggin" <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 8180540..182f9d4 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -206,7 +206,7 @@
 
 static inline int pte_special(pte_t pte)
 {
-	return pte_val(pte) & _PAGE_SPECIAL;
+	return pte_flags(pte) & _PAGE_SPECIAL;
 }
 
 static inline unsigned long pte_pfn(pte_t pte)