drm/amd/display: dc_link_set_psr_allow_active refactoring

[Why]
To expose new power optimization flags to PSR interface. It allows the
PSR related power features can be enabled separately base on different
use scenarios.

Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Agustin Gutierrez <agustin.gutierrez@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Robin Chen <po-tchen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>