Instead of manually creating driver-specific device attributes
set struct driver->dev_groups pointer to have the driver core
do it.

This also fixes issue with the attribute not being deleted on driver
unbind.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/Zo9nofWJ1xg9MgKs@google.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>