Driver core: make sysfs uevent-attributes static

Attributes do not have an owner(module) anymore, so there is no need
to carry the attributes in every single bus instance.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>