Switch hawaii and bonaire to use powerplay rather than the old
dpm implementation.  Powerplay supports more features and is
better maintained.  Ultimately, we can drop the older dpm
implementation like we did for other older asics.
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Rex Zhu <rezhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>