travis: use travis_wait to wait a little longer without output (20min instead of 10min)

.travis.yml

@@ -26,4 +26,4 @@ matrix:
   - env: ARCH=x86_64 SYSTEM=pcengines-apu
   - env: ARCH=x86_64 SYSTEM=asus-p5bvm
   - env: ARCH=xtensa SYSTEM=xilinx-kintex7
-script: ./scripts/travis.sh $ARCH $SYSTEM $ENDIAN
+script: travis_wait ./scripts/travis.sh $ARCH $SYSTEM $ENDIAN