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

The SMUMGR is one sub-component of powerplay for SMU firmware support.
The SMU handles firmware loading for other IP blocks (GFX, SDMA, etc.)
on VI parts.  The adds the core powerplay infrastructure to handle that.

v3: direct use printk in powerplay module.
v2: direct use cgs_read/write_register functions in smu-modules

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>