Display lists contain lists of registers and associated values to be
applied atomically by the hardware. They lower the pressure on interrupt
processing delays when reprogramming the device as settings can be
prepared well in advance and queued to the hardware without waiting for
the end of the current frame.

Display list support is currently limited to the DRM pipeline.
Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>