Fix style(9) and remove m_freem(NULL).
Add XXX comment, it looks incorrect, because m_pkthdr.len is already
incremented by M_PREPEND().

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Merge remote-tracking branch 'freebsd/master' into hardened/current/master
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/segvguard
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/log
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/userlandenhanced
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/unstable
Merge remote-tracking branch 'origin/hardened/current/segvguard' into hardened/current/unstable
Merge remote-tracking branch 'origin/hardened/current/log' into hardened/current/unstable
Merge remote-tracking branch 'origin/hardened/current/userlandenhanced' into hardened/current/unstable