[RFCLAT#10] remove libnl related files

libnl is not required anymore. remove all related files.

Bug: 212345928
Test: atest clatd_test and manual test
1. Connect to ipv6-only wifi.
2. Try IPv4 traffic.
   $ ping 8.8.8.8

Change-Id: Ic4725ef01667576f2a958f38d458374c2e749569
10 files changed