resolve open review comments wrt. libnetd_offloadutils

This library is not needed and was just added in:
  commit 9ce7e66f
  netd_integration_test - add a test for bpf_skb_change_head at mtu limit

Test: atest
Bug: 149816401
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Idac6defff88e98fc12de16eeffd8efec248bbbe6