staging: drm/omap: multiplanar and YUV support

Add support in framebuffer objects for other color formats and multi-
planar YUV (NV12).  Since this requires changing the API between the
plane and fb for getting scanout information (paddr, etc), take
advantage of the opportunity and put in place a way to allow fb's to
be unpinned when they are not being scanned out.  Now, before start
of scanout the plane calls omap_framebuffer_pin() which takes care
to pin all the backing bo's, then omap_framebuffer_update_scanout()
however many times to update the scanout address(es), etc, and then
when finished omap_framebuffer_unpin().

Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>