media: dt-bindings: media: rockchip-rga: add rockchip,rk3588-rga3

media: dt-bindings: media: rockchip-rga: add rockchip,rk3588-rga3

Add a new compatible for the RGA3 (Raster Graphic Acceleration 3)
peripheral found on the RK3588 SoC. Also specify an iommu property,
as the RGA3 contains the generic rockchip iommu. While other versions
also have an iommu, it's usually specific to them.

The RK3588 contains one RGA2-Enhance core (also contained on the RK3399)
and two RGA3 cores. Both feature a similar functionality of scaling,
cropping and rotating of up to two input images into one output image.
Key differences of the RGA3 are:

- supports 10bit YUV output formats
- supports 8x8 tiles and FBCD as inputs and outputs
- supports BT2020 color space conversion
- max output resolution of (8192-64)x(8192-64)
- MMU can map up to 32G DDR RAM
- fully planar formats (3 planes) are not supported
- max scale up/down factor of 8 (RGA2 allows up to 16)

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Sven Püschel <s.pueschel@pengutronix.de>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>