hwc: Replace metadata ioctl reading with sysfs node

  Metadata ioctl approach has limitations with respect
  to adding new capabilities in MDSS driver.
  Use sysfs node mechanism to obtain MDSS capabilities.
  (sysfs node: /sys/class/graphics/fb0/mdp/caps)

Change-Id: Id7fe683c85b3acf182920d28abf62e9826ff1161
2 files changed