[PATCH] x86-64 pmd corruption fix.

Silly typo caused strange corruption.

With this fixed, agpgart almost works again on x86-64
(change_page_attr() seems broken there)

arch/x86_64/mm/init.c

@@ -161,7 +161,7 @@ static  struct temp_map {
 } temp_mappings[] __initdata = { 
 	{ &temp_boot_pmds[0], (void *)(40UL * 1024 * 1024) },
 	{ &temp_boot_pmds[1], (void *)(42UL * 1024 * 1024) }, 
-	{ &temp_boot_pmds[1], (void *)(44UL * 1024 * 1024) }, 
+	{ &temp_boot_pmds[2], (void *)(44UL * 1024 * 1024) }, 
 	{}
 };