drm/amd/pp: Add custom power profile mode support on Vega10

v2: delete uncessary blank line.
    Add static const modifiers to an array

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>