update 3rdparty build shell script

guowenxue

2019-08-11 cdec77818bad5d64e1e3656645f49261f2cc3501

linux-bsp/tarballs/linux-at91.tar.xz does not exist in tree a28f1043c1e62b4ecc3fc9ea66c0b19c3c84c4b6