[media] DVB: Delete an unnecessary check before the function call "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/dvb-core/dvb_ca_en50221.c

@@ -1728,8 +1728,7 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter,
 
 error:
 	if (ca != NULL) {
-		if (ca->dvbdev != NULL)
-			dvb_unregister_device(ca->dvbdev);
+		dvb_unregister_device(ca->dvbdev);
 		kfree(ca->slot_info);
 		kfree(ca);
 	}