CONFIG_ARCH_TEGRA_2x_SOC is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Enable support for Tegra20 family

modulename: powergate.ko

and/or

tegra2_clocks.ko

and/or

tegra2_emc.ko

configname: CONFIG_ARCH_TEGRA_2x_SOC

Linux Kernel Configuration
└─>Enable support for Tegra20 family
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
Support for NVIDIA Tegra AP20 and T20 processors, based on the
ARM CortexA9MP CPU and the ARM PL310 L2 cache controller

source code:
arch/arm/mach-tegra/powergate.c