powerpc/pseries/cmm: Remove unneeded variable "ret"

Remove unneeded variable: "ret".
Signed-off-by: zuoqilin <zuoqilin@yulong.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Just return NOTIFY_OK directly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326075619.48-1-zuoqilin1@163.com

arch/powerpc/platforms/pseries/cmm.c

@@ -475,8 +475,6 @@ static struct notifier_block cmm_reboot_nb = {
 static int cmm_memory_cb(struct notifier_block *self,
 			unsigned long action, void *arg)
 {
-	int ret = 0;
-
 	switch (action) {
 	case MEM_GOING_OFFLINE:
 		mutex_lock(&hotplug_mutex);
@@ -493,7 +491,7 @@ static int cmm_memory_cb(struct notifier_block *self,
 		break;
 	}
 
-	return notifier_from_errno(ret);
+	return NOTIFY_OK;
 }
 
 static struct notifier_block cmm_mem_nb = {