media: i2c: adv748x: configure number of lanes used for TXA CSI-2 transmitter

The driver fixed the TXA CSI-2 transmitter in 4-lane mode while it could
operate using 1-, 2- and 4-lanes. Update the driver to support all
available modes.

The driver makes use of large tables of static register/value writes
when powering up/down the TXA and TXB transmitters which include the
write to the NUM_LANES register. By converting the tables into functions
and using parameters the power up/down functions for TXA and TXB power
up/down can be merged and used for both transmitters.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>