powerpc/pseries/cmm: Report errors when registering notifiers fails

If we don't set the rc, we will return "0", making it look like we
succeeded.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191031142933.10779-3-david@redhat.com

arch/powerpc/platforms/pseries/cmm.c

@@ -683,8 +683,12 @@ static int cmm_init(void)
 	if ((rc = cmm_sysfs_register(&cmm_dev)))
 		goto out_reboot_notifier;
 
-	if (register_memory_notifier(&cmm_mem_nb) ||
-	    register_memory_isolate_notifier(&cmm_mem_isolate_nb))
+	rc = register_memory_notifier(&cmm_mem_nb);
+	if (rc)
+		goto out_unregister_notifier;
+
+	rc = register_memory_isolate_notifier(&cmm_mem_isolate_nb);
+	if (rc)
 		goto out_unregister_notifier;
 
 	if (cmm_disabled)