linux-boundary (3.10.17): add CONFIG_USB_G_MULTI

Signed-off-by: Simon Kuhnle <simon.kuhnle@methodpark.de>
Tested-by: Eric Nelson <eric.nelson@boundarydevices.com>
Acked-by: Eric Nelson <eric.nelson@boundarydevices.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>