powerpc/pseries: Cleanup use of notifier_from_errno()

Minor cleanup of notifier_from_errno() in powerpc.

notifier_from_errno() now contains the if(ret)/else conditional.
There is no need to do it in the powerpc code.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/cmm.c

@@ -508,12 +508,7 @@ static int cmm_memory_isolate_cb(struct notifier_block *self,
 	if (action == MEM_ISOLATE_COUNT)
 		ret = cmm_count_pages(arg);
 
-	if (ret)
-		ret = notifier_from_errno(ret);
-	else
-		ret = NOTIFY_OK;
-
-	return ret;
+	return notifier_from_errno(ret);
 }
 
 static struct notifier_block cmm_mem_isolate_nb = {
@@ -635,12 +630,7 @@ static int cmm_memory_cb(struct notifier_block *self,
 		break;
 	}
 
-	if (ret)
-		ret = notifier_from_errno(ret);
-	else
-		ret = NOTIFY_OK;
-
-	return ret;
+	return notifier_from_errno(ret);
 }
 
 static struct notifier_block cmm_mem_nb = {