RGB LCD panel with sunxi_drm

[Rui-Xiang Guo <rxg%lavabit.com@localhost>]

Hi,
"simple-panel" and "display-timings" definitions are added into the dts file,
but get the error from dmesg on 10.0:
[   1.0000040] sunxidrm0: [drm] Cannot find any crtc or sizes
[   1.0000040] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[   1.0000040] [drm] No driver support for vblank timestamp query.
[   1.0000040] [drm] Initialized sunxi 1.0.0 20190123 for sunxidrm0 on minor 0
[   1.0000040] sunxidrm0: initialized sunxi 1.0.0 20190123 on minor 0

I note that get_modes function is NULL in fdt_panel.c.
Is it possiable to implement it in these cases without EDID detection,
like panel-simple.c on Linux?

-rxg