usb/gadget: free opts struct on error recovery

Fix memory leaks introduced in commits:

40d133d7f542616cf9538508a372306e626a16e9
usb: gadget: f_ncm: convert to new function interface with backward compatibility

fee562a6450b7806f1fbbe1469a67b5395b5c10a
usb: gadget: f_ecm: convert to new function interface with backward compatibility

fcbdf12ebef73a6069e2a1aada1e546fb578a4aa
usb: gadget: f_phonet: convert to new function interface with backward compatibility

b29002a157940752dfed2c488b2011f63f007d71
usb: gadget: f_eem: convert to new function interface with backward compatibility

8cedba7c73af1369599b1111639cfeb66fe13aaa
usb: gadget: f_subset: convert to new function interface with backward compatibility

f466c6353819326873fa48a02c6f2d7c903240d6
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>
diff --git a/drivers/usb/gadget/f_ecm.c b/drivers/usb/gadget/f_ecm.c
index 5d3561e..edab45d 100644
--- a/drivers/usb/gadget/f_ecm.c
+++ b/drivers/usb/gadget/f_ecm.c
@@ -959,8 +959,11 @@
 	mutex_init(&opts->lock);
 	opts->func_inst.free_func_inst = ecm_free_inst;
 	opts->net = gether_setup_default();
-	if (IS_ERR(opts->net))
-		return ERR_PTR(PTR_ERR(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, "", &ecm_func_type);