drm/amdgpu: enable BACO runpm by default on sienna cichlid and navy flounder

It works fine and was only disabled because primary GPUs
don't enter runpm if there is a console bound to the fbdev due
to the kmap.  This will at least allow runpm on secondary cards.

Reviewed-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>