Transceiver: Add missing include netinet/in.h
Transceiver: Add missing include netinet/in.h

Previous commit started using IPPROTO_UDP without including required
include. Newer versions of libosmocore's osmocom/core/socket.h include
that header so the define is present, but older versions of libosmocore
(such as 0.12.0) don't, so let's include it explicitly (the correct
thing to do).

Fixes: b9d2515704ac83cacd88d0a73ecba30323df0b2d
Change-Id: I67ddf550f3a7fc6a650e1e1d9bde0bbb28785104

osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx