drm/amd/powerplay: Add Tonga SMU support

The SMU manager handles firmware loading for other IP
blocks (GFX, SDMA, etc.).  This implements it for Tonga.

v3: delete peci sub-module
v2: use cgs interface directly

Signed-off-by: Young Yang <Young.Yang@amd.com>
Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>