drm/amdgpu: disable BACO support for 699F:C7 polaris12 SKU temporarily

We have a S3 issue on that SKU with BACO enabled. Will bring back this
when that root caused.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>