usb: gadget: f_subset: replace PTR_RET with PTR_ERR_OR_ZERO

PTR_RET is deprecated. Do not recommend its usage anymore.
Use PTR_ERR_OR_ZERO instead.
Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_subset.c

@@ -276,7 +276,7 @@ static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	}
 
 	net = gether_connect(&geth->port);
-	return PTR_RET(net);
+	return PTR_ERR_OR_ZERO(net);
 }
 
 static void geth_disable(struct usb_function *f)