mediatek-drm driver reported the capability of 180-degree rotation by
adding `DRM_MODE_ROTATE_180` to the plane property, as flip-x combined
with flip-y equals a 180-degree rotation. However, we did not handle
the rotation property in the driver and lead to rotation issues.
Fixes: 74608d8feefd ("drm/mediatek: Add DRM_MODE_ROTATE_0 to rotation property")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>