[Feature Request]: Auto max bit color depth for rockchip devices

### Which feature would you like to have?

drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c L2489

if ((hdmi->colordepth > 8 || hdmi->colordepth == 0) && support_dc)
color_depth = 10;
else
color_depth = 8;

Auto default to 10 bit color for supported displays. Defaulting to 8bit kills ability to playback HDR content on wayland hard locking without .dtb modifications

colordepth values enum (0 Automatic, 8 8 bit, 10 10 bit)
0>8 therefore defaults to 8bit color (defaults to min)

### Funding

- [ ] [I am willing to cover expenses](https://www.armbian.com/contact/)

Start at drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c around line 2489 and trace how colordepth and support_dc determine the selected depth. Confirm the automatic setting selects the maximum supported depth for compatible displays and preserves explicit 8-bit or 10-bit settings; validate HDR playback behavior on Wayland with a supported Rockchip device.

Written by the indexing model from the issue text.