dumbfb: Add support tri- or quadri-planar buffers
dumbfb: Add support tri- or quadri-planar buffers

The DumbFrameBuffer class supports up to 4 planes, as required by the
DRM/KMS API, but only considers planes 0 and 1 when constructing the
buffer. Fix it.

Signed-off-by: Laurent Pinchart <3ded2f39a78f0d7044839546f95841842b4d7c96@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <e1ca4dbb8be1acaf20734fecd2da10ed1d46a9bb@ti.com>

tomba/kmsxx,tomba/kmsxx,tomba/kmsxx,tomba/kmsxx