Three changes for the Armada DRM driver:
1. Add back the flags which tell the DRM core that we can do vblank.  This
   was removed in error during the recent restructuring, and came to light
   while trying textured Xv rendering.

2. Fixing a refcount leak with Xv overlay.

3. As per recent discussion, the drm_vblank_pre_modeset() calls can cause
   deadlock with other changes to generic code.  This change prevents those
   deadlocks by switching to the drm_crtc_vblank_*() calls instead.

* 'drm-armada-fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  drm/armada: convert to use vblank_on/off calls
  drm/armada: fix page_flip refcounting leak
  drm/armada: add IRQ support back