spi loopback test framework support

modulename: spi-loopback-test.ko

configname: CONFIG_SPI_LOOPBACK_TEST

Linux Kernel Configuration
└─>Device Drivers
└─>SPI support
└─>spi loopback test framework support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This enables the SPI loopback testing framework driver

primarily used for development of spi_master drivers
and to detect regressions

source code:
depends
CONFIG_MODULES
CONFIG_SPI
CONFIG_SPI_MASTER