IDE: remove rwsem use from ide-proc core

The subsystem rwsem is not used by the driver core at all, so the use of
it in the ide-proc code of it doesn't make any sense.  Perhaps a local
lock might be needed, but I do not really think so.

Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: linux ide <linux-ide@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>