usb: gadget: Update config for SuperSpeedPlus

When a function is added to a configuration with usb_add_function(), the
configuration speed flags are updated. These flags indicate for which
speeds the configuration is valid for.

This patch adds a flag in the configuration for SuperSpeedPlus and
also updates this based on the existence of ssp_descriptors.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/configfs.c

@@ -1229,6 +1229,7 @@ static void purge_configs_funcs(struct gadget_info *gi)
 		}
 		c->next_interface_id = 0;
 		memset(c->interface, 0, sizeof(c->interface));
+		c->superspeed_plus = 0;
 		c->superspeed = 0;
 		c->highspeed = 0;
 		c->fullspeed = 0;