sysfs: Introducing binary attributes for struct class

Added dev_bin_attrs to struct class similar to existing dev_attrs.

Signed-off-by: Stefan Achatz <erazor_de@users.sourceforge.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>