drm/panel: Changes for v3.15-rc1

Add support for a couple more simple panels. A few cleanups to the
simple panel driver are also included (gpiod interface conversion,
removal of redundant call to regulator_disable()).

* tag 'drm/panel/for-3.15-rc1' of git://anongit.freedesktop.org/tegra/linux:
  drm/panel: add support for LG LD070WX3-SL01 panel
  drm/panel: add support for LG LH500WX1-SD03 panel
  drm/panel: simple: Allow DSI panels to provide mode flags
  drm/panel: simple: Allow GPIO accesses to sleep
  drm/panel: remove redundant regulator_disable()
  drm/panel: use gpiod interface for enable GPIO
  drm/panel: Add LG 12.9" LCD panel
  MAINTAINERS: Add entry for DRM panel drivers

Conflicts:
	MAINTAINERS