Merge remote-tracking branch 'quic/dev/msm-4.14-display' into msm-4.14

* quic/dev/msm-4.14-display:
  drm/msm/sde: disable write operation on eventlog dump node
  drm/msm/sde: add null check for current master
  drm/msm/sde: update mixercount check in writeback usecase

Change-Id: I6439598f35b32588094bc2a3783ea88f67f6e2f5
Signed-off-by: Abhijith Desai <desaia@codeaurora.org>