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

NVIDIA Tegra

modulename: gpio-tegra.ko

configname: CONFIG_ARCH_TEGRA

ARM system type
└─>NVIDIA Tegra
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
This enables support for NVIDIA Tegra based systems (Tegra APX,
Tegra 6xx and Tegra 2 series).

source code:
drivers/gpio/gpio-tegra.c