media: rcar-csi2: Prepare for C-PHY support

Gen4 will support both D-PHY and C-PHY, while Gen3 only supports D-PHY.
Add two flags to the device information structure to be able to record
what each SoC supports.

Extend the device node parsing to accept both CSI_2 D-PHY and C-PHY
buses, while at the same time taking the SoC support into account.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
[Sakari Ailus: Line wrap.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>