usb: gadget: add SS descriptors to Ethernet gadget

Add SuperSpeed descriptors to the Network USB
function drivers.

This has been lightly tested using a Linux host.
I was able to ssh from device to host and host to
device, no obvious problems seen.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index ac41858..aafc84f 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -401,7 +401,7 @@
 	.name		= "g_ether",
 	.dev		= &device_desc,
 	.strings	= dev_strings,
-	.max_speed	= USB_SPEED_HIGH,
+	.max_speed	= USB_SPEED_SUPER,
 	.unbind		= __exit_p(eth_unbind),
 };