Revert "genetlink: fix family dump race"

This reverts commit bba2a9f0d381e510ba32f2f984e5ae1e705c90d1 which is
commit 58ad436fcf49810aa006016107f494c9ac9013db upstream, as there are
reported problems with it.

Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>