usb/gadget: free opts struct on error recovery

Fix memory leaks introduced in commits:

40d133d7f5
usb: gadget: f_ncm: convert to new function interface with backward compatibility

fee562a645
usb: gadget: f_ecm: convert to new function interface with backward compatibility

fcbdf12ebe
usb: gadget: f_phonet: convert to new function interface with backward compatibility

b29002a157
usb: gadget: f_eem: convert to new function interface with backward compatibility

8cedba7c73
usb: gadget: f_subset: convert to new function interface with backward compatibility

f466c63538
usb: gadget: f_rndis: convert to new function interface with backward compatibility

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/f_subset.c

@@ -505,8 +505,11 @@ static struct usb_function_instance *geth_alloc_inst(void)
 	mutex_init(&opts->lock);
 	opts->func_inst.free_func_inst = geth_free_inst;
 	opts->net = gether_setup_default();
-	if (IS_ERR(opts->net))
-		return ERR_CAST(opts->net);
+	if (IS_ERR(opts->net)) {
+		struct net_device *net = opts->net;
+		kfree(opts);
+		return ERR_CAST(net);
+	}
 
 	config_group_init_type_name(&opts->func_inst.group, "",
 				    &gether_func_type);