USB: g_printer required set interface request

g_printer reqiured "set interface" request from host. Not all hosts send
this request.  This patch enable the interface when it get "set
configuration" request from host.
Signed-off-by: Jonas Andersson <jonas@microbit.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/printer.c

@@ -1189,6 +1189,8 @@ printer_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 			else if (gadget->a_alt_hnp_support)
 				DBG(dev, "HNP needs a different root port\n");
 			value = printer_set_config(dev, wValue);
+			if (!value)
+				value = set_interface(dev, PRINTER_INTERFACE);
 			break;
 		case USB_REQ_GET_CONFIGURATION:
 			if (ctrl->bRequestType != USB_DIR_IN)