usb: composite: Add .reset callback to usb_gadget_driver structure

DWC3 UDC driver requires presence of .reset callback in a composite driver.
This setting is similar to the one nowadays present in linux kernel.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 729a0fa..d96296c 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1052,6 +1052,7 @@
 	.unbind         = composite_unbind,
 
 	.setup		= composite_setup,
+	.reset          = composite_disconnect,
 	.disconnect	= composite_disconnect,
 
 	.suspend        = composite_suspend,