[media] dvb-core: Release semaphore on error path dvb_register_device()

There is a missing "up_write()" here. Semaphore should be released
before returning error value.

Cc: stable@kernel.org
Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/dvb-core/dvbdev.c

@@ -243,6 +243,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
 	if (minor == MAX_DVB_MINORS) {
 		kfree(dvbdevfops);
 		kfree(dvbdev);
+		up_write(&minor_rwsem);
 		mutex_unlock(&dvbdev_register_lock);
 		return -EINVAL;
 	}