[media] af9035: unlock on error in af9035_i2c_master_xfer()

We introduced a couple new error paths which are missing unlocks.
Fixes: 7760e148350b ('[media] af9035: Don't use dynamic static allocation')

Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Antti Palosaari <[e-mail]>
Signed-off-by: Antti Palosaari <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Cc: [e-mail]

drivers/media/usb/dvb-usb-v2/af9035.c

···
 				dev_warn(&d->udev->dev,
 					 "%s: i2c xfer: len=%d is too big!\n",
 					 KBUILD_MODNAME, msg[0].len);
-				return -EOPNOTSUPP;
+				ret = -EOPNOTSUPP;
+				goto unlock;
 			}
 			req.mbox |= ((msg[0].addr & 0x80)  >>  3);
 			buf[0] = msg[1].len;
···
 				dev_warn(&d->udev->dev,
 					 "%s: i2c xfer: len=%d is too big!\n",
 					 KBUILD_MODNAME, msg[0].len);
-				return -EOPNOTSUPP;
+				ret = -EOPNOTSUPP;
+				goto unlock;
 			}
 			req.mbox |= ((msg[0].addr & 0x80)  >>  3);
 			buf[0] = msg[0].len;
···
 		ret = -EOPNOTSUPP;
 	}
 
+unlock:
 	mutex_unlock(&d->i2c_mutex);
 
 	if (ret < 0)