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
diff --git a/libqservice/IQService.h b/libqservice/IQService.h
index 5054578..0f69d40 100644
--- a/libqservice/IQService.h
+++ b/libqservice/IQService.h
@@ -69,6 +69,7 @@
         GET_CONFIG_COUNT = 27, //Get the number of supported display configs
         GET_DISPLAY_ATTRIBUTES_FOR_CONFIG = 28, //Get attr for specified config
         SET_DISPLAY_MODE = 29, // Set display mode to command or video mode
+        SET_CAMERA_STATUS = 30, // To notify display when camera is on and off
         COMMAND_LIST_END = 400,
     };