Add linux/s390x to cross-compile platforms
Add linux/s390x to cross-compile platforms

gabemontero/source-to-image,coreydaley/source-to-image,gabemontero/source-to-image,gabemontero/source-to-image,openshift/source-to-image,coreydaley/source-to-image,soltysh/source-to-image,coreydaley/source-to-image,soltysh/source-to-image,soltysh/source-to-image,openshift/source-to-image,gabemontero/source-to-image,soltysh/source-to-image,coreydaley/source-to-image,openshift/source-to-image