drm/bridge: ps8622: Delete an unnecessary check before backlight_device_unregister()

The backlight_device_unregister() function tests whether its argument
is NULL and then returns immediately.
Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/791089e4-201c-ad01-9c3b-f49835765177@users.sourceforge.net

drivers/gpu/drm/bridge/parade-ps8622.c

@@ -636,9 +636,7 @@ static int ps8622_remove(struct i2c_client *client)
 {
 	struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);
 
-	if (ps8622->bl)
-		backlight_device_unregister(ps8622->bl);
-
+	backlight_device_unregister(ps8622->bl);
 	drm_bridge_remove(&ps8622->bridge);
 
 	return 0;