tcpd.h: add prototype for hosts_ctl

According the hosts_access(3) man page the hosts_ctl() prototype
should be in tcpd.h. For now, follow other declarations and don't
add the arguments in the prototype.

Reference:
https://www.illumos.org/issues/4385

PR:		32808
MFC after:	2 weeks
Bump FreeBSD_version due to cleanup of tcp wrapper header.

Due to revisions r272949 and r272950 which should affect
positively some ports.