driver core: move uevent call to driver_register

Device driver attribute groups are created after userspace is notified
via an add event. Fix this by moving the kobject_uevent call to
driver_register after the attribute groups are added.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>