CONFIG_SPI_ETRAX_GPIO is not available for thedefaultarchitecture x86.
Result is shown for architecture cris

CONFIG_SPI_ETRAX_GPIO (not configurable)

configname: CONFIG_SPI_ETRAX_GPIO

Linux Kernel Configuration
└─>SPI_ETRAX_GPIO
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
This enables using GPIO pins port as a SPI master controller
on Axis ETRAX FS and later. The driver can be configured to
use any GPIO pins.