driver core: don't trigger uevent after failure

Do not send the uevent if driver_add_groups failed.

Reported-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>