route/link: Check for null pointer in macvlan
route/link: Check for null pointer in macvlan

In cases where link->l_info is not set, a null-ptr-exception
will be invoked.

https://github.com/thom311/libnl/pull/238

greearb/libnl-ct,greearb/libnl-ct,thom311/libnl,thom311/libnl,thom311/libnl,greearb/libnl-ct