And also a leftover to net/ipv4/af_inet.c

And some leftovers from previous changesets also moved to net/core/dev.c
and net/sched/sch_api.c

Also fix a typo.

Also move the EXPORT_SYMBOL(tcp_statistics) to net/ipv4/tcp.c, so that
finally the tcp.h header can be removed from net/netsyms.c, ctags doesn't
catches the variables defined with DEFINE_SNMP_STAT :-\