Commit
b4af427c74fd6c9a428e6f68db5f178285a54c1b
by Pau Espin PedrolPort pfcp socket to osmo_iofd
As a indirect consequence, the pfcp socket now earns a Tx queue, which
should avoid sporadic tx msg drops during high load.
Related: OS#6714
Change-Id: If85888b6857899e0aca1fdd1d806c53476b4d239