drm/vmwgfx: Implement STDU plane update for surface backed fb

Using the new interface implement STDU plane update for surface backed
fb.

v2: Rebase to new resource validation.

Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>