HEADS UP: DRM/KMS graphics driver updates

[Taylor R Campbell <campbell+netbsd-tech-x11%mumble.net@localhost>]

NetBSD's DRM/KMS graphics drivers are currently based on Linux 3.15,
plus some backports.  Several of us (me, maya, mrg, leot) have been
working on updating the kernel graphics drivers (i915drmkms, radeon,
nouveau, and now amdgpu).  We did Linux 4.4 as an intermediate step
toward newer graphics, probably 4.18.  My state is in the git branch
riastradh-drm at <https://github.com/riastradh/netbsd-src.git>.

Right now, it works in cursory testing on i945, Ivy Bridge, Haswell,
and Skylake, and some radeon devices.  Unfortunately, with nouveau it
just blanks the screen and I haven't been able to figure out why.

Nevertheless, I'm planning to commit this to CVS soon so we can get to
work on 4.18 rather than get bogged down debugging 4.4 (and maybe
we'll figure out what's wrong with our 4.4 nouveau anyway -- probably
a really stupid bug like most of them have been), but still have 4.4
available for some newer hardware support than 3.15 in case netbsd-9
is ready before we make 4.18 work.