x86-64: don't check for map replacement

The check prevents flags on mappings from being changed, which is not
desireable.  There's no need to check for replacing a mapping, and
x86-32 does not do this check.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5beb896..7c8bb46 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -196,9 +196,6 @@
 	}
 
 	pte = pte_offset_kernel(pmd, vaddr);
-	if (!pte_none(*pte) && pte_val(new_pte) &&
-	    pte_val(*pte) != (pte_val(new_pte) & __supported_pte_mask))
-		pte_ERROR(*pte);
 	set_pte(pte, new_pte);
 
 	/*