[media] ddbridge: remove unneeded check before dvb_unregister_device()

The dvb_unregister_device() 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: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/pci/ddbridge/ddbridge-core.c

@@ -1118,8 +1118,7 @@ static void ddb_ports_detach(struct ddb *dev)
 			dvb_input_detach(port->input[1]);
 			break;
 		case DDB_PORT_CI:
-			if (port->output->dev)
-				dvb_unregister_device(port->output->dev);
+			dvb_unregister_device(port->output->dev);
 			if (port->en) {
 				ddb_input_stop(port->input[0]);
 				ddb_output_stop(port->output);