hwc : Set bw limit on mdss when camera is on.

-Expose qservice API to get notified when Camera is on or off.
-Set bandwidth hint to mdss based on camera launch status by
  writing into fb0/mdp/bw_mode_bitmap.
-Implement camera service death notifier to recover display bw.

Change-Id: I532f44281b5d7de1d638f1cef250114a3cc952ae
4 files changed