staging: lustre: get entropy from nid when nid set.

When the 'lustre' module is loaded, it gets a list of
net devices and uses the node ids to  add entropy
to the prng.  This means that the network interfaces need
to be configured before the module is loaded, which prevents
the module from being compiled into a monolithic kernel.

So move this entropy addition to the moment when
the interface is imported to LNet and the node id is first known.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>