[Buildroot] [PATCH 1/3] configs: add defconfig for Nationalchip gx6605s dev board.

[ren_guo]

> +BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="https://github.com/c-sky/linux-4.9.y/archive/HEAD.tar.gz"
>
Sorry, I forgot to change HEAD to commit log, and I will do it again.