drm/amdgpu/mes: fix mes12 to map legacy queue

Adjust mes12 initialization sequence to fix mapping
legacy queue.

v2: use dev_err.

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>