improve comments in gpio_test
improve comments in gpio_test

janick/libsoc,vagrantc/libsoc,hlummis/libsoc,hlummis/libsoc,janick/libsoc,jackmitch/libsoc,janick/libsoc,vagrantc/libsoc,yegorich/libsoc,jackmitch/libsoc,hlummis/libsoc,yegorich/libsoc,vagrantc/libsoc,jackmitch/libsoc,janick/libsoc,yegorich/libsoc,hlummis/libsoc