There is only a minor kernel configuration change, so you can alter the kernel configuration yourself after loading the default Buildroot config for you board.
thanks for the hint, another question related to buildroot...
i see that kernel patches under /linux directory are applied during compilation, but my patches in kernel-patches directory of my board directory not.
modifying BR2_LINUX_KERNEL_PATCH in my defconfig to my board kernel-patches directory results in /linux patches not applied.
how can i make it work?