Use numDisplays instead of MAX_DISPLAYS in hwcomposer reset() function

Change-Id: I98ee5f6bda680548aa0c7701e17f8a7e4e8d454c
Merge "Use numDisplays instead of MAX_DISPLAYS in hwcomposer reset() function" into cm-11.0
Merge remote-tracking branch 'cm/cm-11.0' into HEAD