drm/amdgpu: enable RAS feature for more mmhub sub-blocks of Acrturus

Compared with Vg20, the size of mmhub range is changed from 2 to 8.
Signed-off-by: Dennis Li <Dennis.Li@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>