drm/amd/display: Move PSR support message into amdgpu_dm

[Why]
PSR support could vary from the panels connected to one GPU versus
another.

[How]
Move PSR support message into amdgpu_dm which has the scope of the
GPU and use that information.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>