drm/amdgpu: Support passing amdgpu critical error to host via GPU Mailbox.

This feature works for SRIOV enviroment. For non-SRIOV enviroment, the
trans_error function does nothing.

The error information includes error_code (16bit), error_flags(16bit)
and error_data(64bit). Since there are not many errors, we keep the
errors in an array and transfer all errors to Host before amdgpu
initialization function (amdgpu_device_init) exit.

Signed-off-by: Gavin Wan <Gavin.Wan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>