media: platform: Add Renesas RZ/G2L MIPI CSI-2 receiver driver

Add MIPI CSI-2 receiver driver for Renesas RZ/G2L. The MIPI
CSI-2 is part of the CRU module found on RZ/G2L family.

Based on a patch in the BSP by Hien Huynh
<hien.huynh.px@renesas.com>

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>