drivers/base/attribute_container.c: use mutex instead of binary semaphore

use mutex instead of binary semaphore in
drivers/base/attribute_container.c

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>