setup_board: remove old kernel vars
setup_board: remove old kernel vars

These are properly detected now.

glevand/coreos--scripts,fivethreeo/scripts,marineam/coreos-scripts,trnubo/scripts,endocode/scripts,smilart/scripts,mjg59/scripts,trnubo/scripts,coreos/scripts,zhang0137/scripts,smilart/scripts,sigma/coreos-scripts,coreos/scripts,endocode/scripts,nicescale/scripts,marineam/coreos-scripts,smilart/scripts,fivethreeo/scripts,endocode/scripts,sigma/coreos-scripts,sigma/coreos-scripts,nicescale/scripts,fivethreeo/scripts,marineam/coreos-scripts,zhang0137/scripts,mjg59/scripts,mjg59/scripts,zhang0137/scripts,nicescale/scripts,trnubo/scripts,glevand/coreos--scripts