Custom Kernel using new JetPack

How to add a feature that already exists in linux kernel but not enabled in the default kernel that came with the new release JetPack?

Enable the feature from '/kernel/kernel-4.9/arch/arm64/configs/tegra_defconfig"
And build the kernel image then update it. Have a reference to below link to know how to build the kernel.

https://docs.nvidia.com/jetson/l4t/Tegra%20Linux%20Driver%20Package%20Development%20Guide/kernel_custom.html#