Merge tag 'imx-drm-fixes-2017-10-12' of git://git.pengutronix.de/git/pza/linux into drm-fixes

drm/imx: i.MX5 regression fix and i.MX6QP PRE/PRG stability fixes

- Disable channel burst locking on IPUv3EX (i.MX51) and IPUv3M (i.MX53).
  This fixes a regression introduced by commit 790cb4c7 ("drm/imx: lock
  scanout transfers for consecutive bursts").
- Give PRG a head start. Waiting for both double buffers to fill up before
  enabling the IPU improves startup reliability.
- Avoid PRE control register updates during unsafe window, workaround for
  ERR009624.

* tag 'imx-drm-fixes-2017-10-12' of git://git.pengutronix.de/git/pza/linux:
  gpu: ipu-v3: pre: implement workaround for ERR009624
  gpu: ipu-v3: prg: wait for double buffers to be filled on channel startup
  gpu: ipu-v3: Allow channel burst locking on i.MX6 only