media: rcar-csi2: Add support for MEDIA_BUS_FMT_SRGGB8_1X8 format

This patch adds support for MEDIA_BUS_FMT_SRGGB8_1X8 format for CSI2
input.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>