contrib: Disable libmnl dependency cross-compiling osmo-bts

Only newest OE SDKs have libmnl added, but we don't need this feature
anyway, so let's disable it in order to get builds running fine again.

Change-Id: Ief9cbca6e10b1ed6acf6e079f660fc3f7c863c7b
diff --git a/contrib/jenkins-build-osmo-bts-sysmo.sh b/contrib/jenkins-build-osmo-bts-sysmo.sh
index fc528d3..731867f 100755
--- a/contrib/jenkins-build-osmo-bts-sysmo.sh
+++ b/contrib/jenkins-build-osmo-bts-sysmo.sh
@@ -18,7 +18,7 @@
 prefix_real="$DESTDIR$prefix"
 . "$(dirname "$0")/jenkins-build-common.sh"
 
-build_repo libosmocore --disable-pcsc --disable-doxygen --disable-gnutls --disable-detect-tls-gcc-arm-bug
+build_repo libosmocore --disable-pcsc --disable-libmnl --disable-doxygen --disable-gnutls --disable-detect-tls-gcc-arm-bug
 build_repo libosmo-abis --disable-dahdi
 build_repo osmo-bts --enable-sysmocom-bts --with-openbsc=$base/openbsc/openbsc/include