Fix "net: ipv4: do not handle duplicate fragments as overlapping"

Fix "net: ipv4: do not handle duplicate fragments as overlapping"

ade446403bfb ("net: ipv4: do not handle duplicate fragments as
overlapping") was backported to many stable trees, but it had a problem
that was "accidentally" fixed by the upstream commit 0ff89efb5246 ("ip:
fail fast on IP defrag errors")

This is the fixup for that problem as we do not want the larger patch in
the older stable trees.

Fixes: ade446403bfb ("net: ipv4: do not handle duplicate fragments as overlapping")
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>