drm/amd/powerplay: initialize arcturus MP1 and THM base address

Initialize base address for those IPs which are used in powerplay.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>