media: i2c: imx290: Move registers with fixed value to init array

Registers 0x3012, 0x3013 and 0x3480 are not documented and are set in
the per-mode register arrays with values indentical for all modes. Move
them to the common array.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>