drm/amd/powerplay: helper interfaces for MGPU fan boost feature

MGPU fan boost feature is enabled only when two or more dGPUs
in the system.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
5 files changed