V4L/DVB (10972): zl10353: i2c_gate_ctrl bug fix

zl10353 i2c-gate was always closed and due to that devices having tuner
behind i2c-gate were broken. Add module configuration which allows disabling
i2c-gate only when really needed.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>