rules for merging patches to libdrm

[Dave Airlie]

Since we seemed to have some confusion over this I'll state it clearly here.

You should not merge kernel interface and ioctls to libdrm until they
have appeared in a git commit upstream with a stable id, this
generally means drm-next, but can also mean drm-intel-next.

You shouldn't assume that stuff is in a kernel somewhere, you should
take the 5-10 minutes to ask me and/or check yourself, its not like
kernel trees are a hidden thing,

This rule is something we learned the hard way a long time ago, I'm
sorry my reverting libdrm broke the mesa build, but really if you own
a feature you need to make sure all the parts of it get your
attention.

Dave.