net: fix header include order for FreeBSD

net: fix header include order for FreeBSD

Spotted by sparse in OVS build:

../../lib/netdev-dpdk.c: note: in included file (through
/home/runner/work/ovs/ovs/dpdk-dir/build/include/rte_ip.h,
/home/runner/work/ovs/ovs/dpdk-dir/build/include/rte_flow.h, ...):
../../include/sparse/arpa/inet.h:22:2: error: "Must include
<netinet/in.h> before <arpa/inet.h> for FreeBSD support"

This is a check enforced by OVS itself.
See [1] for some context.

1: https://github.com/openvswitch/ovs/commit/b2befd5bb2db

Fixes: 89813a522e68 ("net: provide IP-related API on any OS")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>