drm/amd/powerplay: enable BACO feature as WAR

It would hit SMU fw bug without BACO enablement when audio
driver put audio device to D3 state. Before the bug in SMU fw
get fixed, enable BACO feature as WAR.

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Acked-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>