Merge branch 'inet-frags-followup'

Eric Dumazet says:

====================
inet: frags: followup to 'inet-frags-avoid-possible-races-at-netns-dismantle'

Latest patch series ('inet-frags-avoid-possible-races-at-netns-dismantle')
brought another syzbot report shown in the third patch changelog.

While fixing the issue, I had to call inet_frags_fini() later
in IPv6 and ilowpan.

Also I believe a completion is needed to ensure proper dismantle
at module removal.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>