[media] OMAP_VOUT: Add support for DSI panels

Add support for DSI panels. DSI video mode panels will work directly. For
command mode panels, we will need to trigger updates regularly. This isn't done
by the omap_vout driver currently. It can still be supported if we connect a
framebuffer device to the panel and configure it in auto update mode.

Signed-off-by: Archit Taneja <archit@ti.com>
Acked-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>