[PATCH v2] drm: don't run atomic_async_check for disabled planes

[Xaver Hugl]

> As said in my earlier comment, this new_state->visible is not yet
> populated. It will be viable to have these after atomic_check where
> state->visible gets updated.
> Instead fb can be checked to see if its changed to NULL then it means
> disable the plane and instead of rejecting the change, can proceed.
Oh, I assumed that visible would be set when setting the properties
(but potentially wrong while not all properties are set yet). I
should've checked where it's actually calculated, sorry about that,
I'll change it to use FB_ID instead.

> These kind of checks will be much easier with having the proposed change
> in RFC https://patchwork.freedesktop.org/series/150081/
Yeah, some cleanups in this area would be amazing :)

- Xaver