drm/amd/display: Add SubVP required code

This commit enables the SubVP feature. To achieve that, we need to:

- Don't force p-state disallow on SubVP (can't block dummy p-state)
- Send calculated watermark to DMCUB for SubVP
- Adjust CAB mode message to PMFW
- Add a proper locking sequence for SubVP
- Various fixes to SubVP static analysis and determining SubVP config
- Currently SubVP not supported with pipe split so merge all pipes
  before setting up SubVp

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>