media: dt-bindings: media: renesas,vin: Add r8a779a0 support

Document support for the VIN module in the Renesas V3U (r8a779a0) SoC.
The V3U is different from other SoCs as it have 32 instead of 8 (most of
Gen3) or 16 (V3H) VIN instances. The VIN instances are also connected to
a new IP the R-Car ISP Channel Selector.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
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>