drm/amd/display: Various fixes for PSR on DMCUB

[Why]
- Driver does not recognize new definitions of psr states.
- Internal tool is required for checking if psr is active.

[How]
- Parse psr state correctly so that driver will recognize psr state.
- Add visual confirmation that psr is active using existing mechanisms.

Signed-off-by: Wyatt Wood <wyatt.wood@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>