drm/amd/display: Request usb4 bw for mst streams

[WHY]
When usb4 bandwidth allocation mode is enabled, driver need to request
bandwidth from connection manager. For mst link,  the requested
bandwidth should be big enough for all remote streams.

[HOW]
- If mst link, the requested bandwidth should be the sum of all mst
  streams bandwidth added with dp MTPH overhead.
- Allocate/deallcate usb4 bandwidth when setting dpms on/off.
- When doing display mode validation, driver also need to consider total
  bandwidth of all mst streams for mst link.

Reviewed-by: Cruise Hung <cruise.hung@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Peichen Huang <peichen.huang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>