[media] ds3000: bail out early on i2c failures during firmware load

- if kmalloc() returns NULL, we can return immediately without trying
   to kfree() a NULL pointer.
 - if i2c_transfer() fails, error out immediately instead of trying to
   upload the remaining bytes of the firmware.
 - the error code is then properly propagated down to ds3000_initfe().

Signed-off-by: Rémi Cardona <remi.cardona@smartjog.com>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>