Final pile of features for 4.13

New uabi:
- batch bo in first slot, for faster execbuf assembly in userspace
  (Chris Wilson)
- (sub)slice getparam, needed for mesa perf support (Robert Bragg)

First pile of patches for cnl/cfl support, maintained by Rodrigo but
with lots of contributions from others. Still incomplete since public
review still ongoing.

Features/refactoring:
- Make execbuf faster (Chris Wilson), a pile of series to make execbuf
  buffer handling have fewer passes, use less list walking, postpone
  more work to async workers and shuffle buffers less, all to make the
  common case much faster (in some cases at least).
- cold boot support for glk dsi (Madhav Chauhan)
- Clean up pipe A quirk and related old platform hacks (Ville)
- perf sampling support for kbl/glk (Lionel)
- perf cleanups (Robert Bragg)
- wire atomic state to backlight code, to avoid pipe lookup hacks
  (Maarten)
- reduce request waiting latency/overhead to remove the spinning and
  associated cpu cycle wasting (Chris)
- fix 90/270 rotation wm computation (Ville)
- new ddb allocation algo for skl (Kumar Mahesh)
- fix regression due to system suspend optimiazatino (Imre)
- the usual pile of small cleanups and refactors all over

GVT updates contained in this tag:
- optimization for per-VM mmio save/restore (Changbin)
- optimization for mmio hash table (Changbin)
- scheduler optimization with event (Ping)
- vGPU reset refinement (Fred)
- other misc refactor and cleanups, etc.