Merge branch 'rhltable-dups'

Paul Blakey says:

====================
rhashtable: Fix rhltable duplicates insertion

On our mlx5 driver fs_core.c, we use the rhltable interface to store
flow groups. We noticed that sometimes we get a warning that flow group isn't
found at removal. This rare case was caused when a specific scenario happened,
insertion of a flow group with a similar match criteria (a duplicate),
but only where the flow group rhash_head was second (or not first)
on the relevant rhashtable bucket list.

The first patch fixes it, and the second one adds a test that show
it is now working.

Paul.

v3 --> v2 changes:
    * added missing fix in rhashtable_lookup_one code path as well.

v1 --> v2 changes:
    * Changed commit messages to better reflect the change
====================

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