drm/amdgpu: add RAS support for VML2 and ATCL2

v1: Add codes to query the EDC count of VML2 & ATCL2
v2: Rename VML2/ATCL2 registers and drop their mask define
v3: Add back the ECC mask for VML2 registers

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