Added instructions for mounting rootfs over NFS
Added instructions for mounting rootfs over NFS

shengzhou/ONL,audihsu-qci/ONL,InterfaceMasters/ONL,iamyaw/ONL,jeankuo/ONL,capveg/ONL,jeankuo/ONL,capveg/ONL,shengzhou/ONL,audihsu-qci/ONL,JS-Wang/ONL,iamyaw/ONL,InterfaceMasters/ONL,JS-Wang/ONL