drm/amdgpu/ucode: add the definitions of MES ucode and ucode data

MES requires two seperate firmwares: ucode and ucode data.

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>