[tcpdump deleted]

This is almost certainly a bug in the new mips-tuned bcopy.

I've reverted sys/arch/mips/conf/files.mips to use netinet/in_cksum.c,
rather than sys/arch/mips/mips/in_cksum.c.  You can do the same,
or wait for tomorrow's sup.

Note too that the new compressed pTCB-state code causes kernel stack
overflow on NetBSD/pmax, so the new checksum might not be a total fix.