MFC r287651, r287652, r287653.

MFC r287651, r287652, r287653.

Fix mutex errors, fixup typos in comments.

Obtained from:	NetBSD r1.4.
-This lie, anr those below, will be ignored--
> Description of fields to fill in above:                     76 columns --|
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> Differential Revision:    https://reviews.freebsd.org/D### (*full* phabric URL needed).
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_M   .
M    sys/contrib/ipfilter/netinet/ip_state.c

git-svn-id: svn://svn.freebsd.org/base/stable/10@287984 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f