drm/amd/display: add addition dc type to translate to dmub fw type

[Why]
For a type like PSR version, it makes sense for most of the code
to include a dc type, instead of having this a fw type define since
this is a capability and type exposed by dc.

Especially if it doesn't even need to communicate with the fw.

The code that is packing the firmware command message
should be the one who needs to translate the psr version
into a command that the firmware understands.

[How]
Add a dc_psr_version enum.

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>