drm/amd/powerplay: add hardware manager sub-component

The hwmgr handles all hardware related calls, including clock/power
gating control, DPM, read and parse PPTable, etc.

v5: squash in fixes
v4: implement acpi's atcs function use cgs interface
v3: fix code style error and add big-endian mode support.
v2: use cgs interface directly in hwmgr sub-module

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