firmware: arm_sdei: Remove while loop in sdei_event_unregister()

This removes the unnecessary while loop in sdei_event_unregister()
because of the following two reasons. This shouldn't cause any
functional changes.

   * The while loop is executed for once, meaning it's not needed
     in theory.
   * With the while loop removed, the nested statements can be
     avoid to make the code a bit cleaner.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200922130423.10173-10-gshan@redhat.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/firmware/arm_sdei.c

@@ -491,11 +491,10 @@ int sdei_event_unregister(u32 event_num)
 
 	mutex_lock(&sdei_events_lock);
 	event = sdei_event_find(event_num);
-	do {
 	if (!event) {
 		pr_warn("Event %u not registered\n", event_num);
 		err = -ENOENT;
-			break;
+		goto unlock;
 	}
 
 	spin_lock(&sdei_list_lock);
@@ -505,10 +504,10 @@ int sdei_event_unregister(u32 event_num)
 
 	err = _sdei_event_unregister(event);
 	if (err)
-			break;
+		goto unlock;
 
 	sdei_event_destroy(event);
-	} while (0);
+unlock:
 	mutex_unlock(&sdei_events_lock);
 
 	return err;