Grabbing modesetting ddx related patches for pull request

[Lyude Paul]

To help ajax out with getting a bug release out for Xorg, we figured it would
be a good idea for me to go through the stuff I needed to get upstream and
file pull requests for all of it. This is pretty much the same thing as what
I'm doing for EGLStreams stuff in Xwayland, except for modesetting.

For starters, my current WIP branch for this pull lives at:

https://gitlab.freedesktop.org/lyudess/xserver/tree/wip/modesetting-pull

This contains all the modesetting patches on patchwork I could find that have
been reviewed and are ready to go. Additionally, there's a rather important
fix for the modesetting ddx regarding the new partial atomic support that I
haven't written up yet that will be included in this too.

Other then that, there's currently some patches on the ML that I found which
need reviews:

 * "modesetting: Update fb_id from shadow allocate and destroy if not set"
   from Tony Lindgren:
   https://patchwork.freedesktop.org/patch/203834/
 * "modesetting: Allow a DRM fd to be passed on command line with -masterfd"
   from Keith Packard
   https://patchwork.freedesktop.org/patch/207655/

I will try to give a review of these, but reviews from others would be
appreciated as well since there are probably people a lot more experienced
with this ddx than I on this list :).

If I've missed anyone's patches, please feel free to respond to this email.
I'll give an update when I think it's ready for pulling time (which should
hopefully not be too long from now).

-- 
Cheers,
	Lyude Paul