gpu/drm: ingenic: Check for display size in CRTC atomic check

Check that the requested display size isn't above the limits supported
by the CRTC.

- JZ4750 and older support up to 800x600;
- JZ4755 supports up to 1024x576;
- JZ4760 and JZ4770 support up to 720p;
- JZ4780 supports up to 2k.

v2: No change

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20191210144142.33143-5-paul@crapouillou.net
# *** extracted tags ***
Acked-by: Sam Ravnborg <sam@ravnborg.org>