- Update config files: Build DSA drivers as modules
    
    DSA drivers can be built as modules since kernel v3.3, so do that:
     - CONFIG_NET_DSA=m
     - CONFIG_NET_DSA_MV88E6XXX=m
     - CONFIG_NET_DSA_MV88E6060=m
     - CONFIG_NET_DSA_MV88E6131=m
     - CONFIG_NET_DSA_MV88E6123_61_65=m