[media] si2168: add support for newer firmwares

Si2168-B40 firmware API has changed somewhere between 4.0-11 and
4.0-19 so that sleep will lose firmware upgrade from the chip. Due
to that firmware re-upload is needed when newer firmwares are used.

Rewrote firmware handling logic partly at the same.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Cc: Olli Salonen <olli.salonen@iki.fi>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>