[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 <dan.carpenter@oracle.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: stable@vger.kernel.org