modules: update routing

02b4dbf (HEAD -> openwrt-19.07, origin/openwrt-19.07) Merge pull request #620 from ecsv/batadv-for-19.07
59e8d5f batctl: Merge bugfixes from 2020.4
6859689 batman-adv: Merge bugfixes from 2020.4

Compile-tested: x86-64
Run-tested: x86-64 (QEMU)