UAPI Changes:

- vc4: Add get/set tiling format ioctls (Eric)

Driver Changes:
- vc4: Add tiling T-format support for scanout (Eric)
- vc4: Use atomic helpers in commit (Boris)

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Eric Anholt <eric@anholt.net>