Now that attribute groups support binary attributes, use them instead of
the dev_bin_attrs field in struct class, as that is going away soon.

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