media: rzg2l-cru: Drop function pointer to configure CSI

media: rzg2l-cru: Drop function pointer to configure CSI

Drop function pointer to configure CSI to avoid code duplication
by checking the presence of vc select register in rzg2l_cru_info.
After this change, limit the scope of the rzg2l_cru_csi2_setup()
to static.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>