media: i2c: Add RDACM20 driver

The RDACM20 is a GMSL camera supporting 1280x800 resolution images
developed by IMI based on an Omnivision 10635 sensor and a Maxim MAX9271
GMSL serializer.

The GMSL link carries power, control (I2C) and video data over a
single coax cable.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>