If a device is already enabled, don't bother reenabling it.
Signed-off-by: NKristen Carlson Accardi <kristen.c.accardi@intel.com>
Acked-By: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>