usb: gadget: dummy_hcd: add SuperSpeed support

This patch adds SS support to the dummy hcd module.
It may be used to test SS device when no (SS) HW is
available.

USB 3.0 hub includes 2 hubs - one HS and one SS. This
patch adds support for a SS root hub in the dummy_hcd
module.

A new module parameter was added: is_super_speed. When
set to true, a SS root hub will also be registered and
the connected device will be enumerated over the SS
root hub. The default of this parameter is false.
Signed-off-by: NTatyana Brokhman <tlinder@codeaurora.org>

[ balbi@ti.com : slight change to commit log
		 fixed one coding style issue ]
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/Kconfig

@@ -631,6 +631,7 @@ config USB_GADGET_DUMMY_HCD
 	boolean "Dummy HCD (DEVELOPMENT)"
 	depends on USB=y || (USB=m && USB_GADGET=m)
 	select USB_GADGET_DUALSPEED
+	select USB_GADGET_SUPERSPEED
 	help
 	  This host controller driver emulates USB, looping all data transfer
 	  requests back to a USB "gadget driver" in the same host.  The host