drm/amdgpu: Rely on MCUMC_STATUS for umc v8_10 correctable error counter only

Only check MCUMC_STATUS for CE counter for umc v8_10.

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