drm/rockchip: Add VOP2 driver

The VOP2 unit is found on Rockchip SoCs beginning with rk3566/rk3568.
It replaces the VOP unit found in the older Rockchip SoCs.

This driver has been derived from the downstream Rockchip Kernel and
heavily modified:

- All nonstandard DRM properties have been removed
- dropped struct vop2_plane_state and pass around less data between
  functions
- Dropped all DRM_FORMAT_* not known on upstream
- rework register access to get rid of excessively used macros
- Drop all waiting for framesyncs

The driver is tested with HDMI and MIPI-DSI display on a RK3568-EVB
board. Overlay support is tested with the modetest utility. AFBC support
on the cluster windows is tested with weston-simple-dmabuf-egl on
weston using the (yet to be upstreamed) panfrost driver support.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Co-Developed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net>
[dt-binding-header:]
Acked-by: Rob Herring <robh@kernel.org>
[moved dt-binding header from dt-nodes patch to here
 and made checkpatch --strict happier]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422072841.2206452-23-s.hauer@pengutronix.de