IEEE1394: remove rwsem use from ieee1394 core

The subsystem rwsem is not used by the driver core at all, so the use of
it in the ieee1394 code doesn't make any sense.  They might possibly
want to use a local lock, but as most of these operations are already
protected by a local lock, it really doesn't look like it would be
needed.

Cc: Ben Collins <bcollins@debian.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: linux1394-devel <linux1394-devel@lists.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>