update linux-bsp build shell script and patch file for new buildroot cross ...

guowenxue

2019-08-11 b901880014f1b2099f7390833ed6eebd97c0e50a

linux-bsp/tarballs/linux-at91.tar.xz does not exist in tree f6304f88395e6923884b59d612e4723f34819464