Merge from OpenBSD:
revision 1.170 date: 2011/10/30 23:04:38; author: mikeb; state: Exp; lines: +6 -7 Allow setting big MTU values on the pfsync interface but not larger than the syncdev MTU. Prompted by the discussion with and tested by Maxim Bourmistrov; ok dlg, mpf
Consistently use sc_ifp->if_mtu in the MTU check throughout the
module. This backs out r228813.