drm/amdgpu: querry umc error count

check umc error count in both ras querry function and
ras interrupt handler

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Dennis Li <dennis.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>