drm/amd/powerplay: Add SMU WMTABLE Validity Check for Renoir

[Why]
SMU watermark table (WMTABLE) validity check is missing on Renoir.
This validity check is very useful for checking whether
WMTABLE is updated successfully.

[How]
Add SMU watermark validity check.

Signed-off-by: Zhan Liu <zhan.liu@amd.com>
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>