media: i2c: imx290: Pass format and mode to imx290_calc_pixel_rate()

Avoid accessing the imx290 current_format and current_mode fields in
imx290_calc_pixel_rate() to prepare for the removal of those fields.
Among the two callers of the function, imx290_ctrl_update() has an
explicit mode pointer already, and we can also give it a format pointer.
Use those explicitly.

While at it, inline the imx290_get_link_freq() function in
imx290_calc_pixel_rate() as it is only called there.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>