media: i2c: imx290: Replace GAIN control with ANALOGUE_GAIN

The IMX290 gain register controls the analogue gain. Replace the
V4L2_CID_GAIN control with V4L2_CID_ANALOGUE_GAIN.

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>