drm/amd/display: Implement wait_for_odm_update_pending_complete

[WHY]
Odm update is doubled buffered. We need to wait for ODM update to be
completed before optimizing bandwidth or programming new udpates.

[HOW]
implement wait_for_odm_update_pending_complete function to wait for:
1. odm configuration update is no longer pending in timing generator.
2. no pending dpg pattern update for each active OPP.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Alex Hung <alex.hung@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>