drm/amd/pm: keep the BACO feature enabled for suspend

To pair with the workaround which always reset the ASIC in suspend.
Otherwise, the reset which relies on BACO will fail.

Fixes: daf8de08 ("drm/amdgpu: always reset the asic in suspend (v2)")

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