Add code to gracefuly handle any pipe reassignment
occuring on dcn3 hardware. This should only happen when new
surfaces are used for an update rather than old ones updated.

Fixes: 69fc1f4b ("amd/drm/display: avoid dcn3 on flip opp change for slave pipes")
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>