x86/pat: Trivial: don't create debugfs for memtype if pat is disabled

If pat is disabled (boot with nopat), there's no need to create
debugfs for it, it's empty all the time.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1259236428-16329-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/pat.c

@@ -1019,8 +1019,10 @@ static const struct file_operations memtype_fops = {
 
 static int __init pat_memtype_list_init(void)
 {
-	debugfs_create_file("pat_memtype_list", S_IRUSR, arch_debugfs_dir,
-				NULL, &memtype_fops);
+	if (pat_enabled) {
+		debugfs_create_file("pat_memtype_list", S_IRUSR,
+				    arch_debugfs_dir, NULL, &memtype_fops);
+	}
 	return 0;
 }