Starting with 4.12 kernel DRM provides page flip flags so we
don't need to have our own copy.
Signed-off-by: NAndrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Reviewed-by: NHarry Wentland <Harry.Wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>