hello aravind.m90,
please extract kernel source package, you should check the hardware folder for the device tree sources.
you may check below path since Xavier NX is based-on t19x chip series, and its platform name is Jakku.
i.e. $L4T_Sources/r32.4.4/Linux_for_Tegra/source/public/hardware/nvidia/platform/t19x/jakku/*