1.Select the smaller downscaling ratio for both sides as
rotator needs do the same downscaling for both direction.
2. Use rotator to do the minimum downscaling first to get the
best quality. Use decimation when rotator downscaling is
not enough.
3. Assign z_order when doing resource configuration.
4. For non src split case, if two pipes are on one mixer,
need make sure right pipe has the different z_order.
Change-Id: I1b829545053c2b719da8b6b42c1e5341a5040bcc
d9408eb428