drm/amd/display: treat plane clip size change as MED update type

[why]
When clip size is changed recout and viewport size would require an
update. When the update is clip size only current driver fails to
program the update into hardware.

[how]
Set a new clip_size_change flag when it is detected and set MED update
type and reprogram scaling params in next program pipe.

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>