back out r1.22, ie, don't blindly trim the FCS on rxed packets.

back out r1.22, ie, don't blindly trim the FCS on rxed packets.

there's been multiple reports of severely reduced throughput using
ure(4) since 1.22 was committed, but all the gear we have to play
with is fine with it. i'm backing the diff out until we can get a
better handle on the problem

discussed with and ok kevlo@ jmatthew@