Merge branch 'rhashtables-cleanups'

NeilBrown says:

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Assorted rhashtables cleanups.

Following 7 patches are selections from a recent RFC series I posted
that have all received suitable Acks.

The most visible changes are that rhashtable-types.h is now preferred
for inclusion in include/linux/*.h rather than rhashtable.h, and
that the full hash is used - no bits a reserved for a NULLS pointer.
====================

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