drm/amdgpu: implement querying ras error count for mmhub

get mmhub ea ras error count by accessing EDC_CNT register

Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
3 files changed