net: usb: fix memory leak in smsc75xx_bind

Syzbot reported memory leak in smsc75xx_bind().
The problem was is non-freed memory in case of
errors after memory allocation.

backtrace:
  [<ffffffff84245b62>] kmalloc include/linux/slab.h:556 [inline]
  [<ffffffff84245b62>] kzalloc include/linux/slab.h:686 [inline]
  [<ffffffff84245b62>] smsc75xx_bind+0x7a/0x334 drivers/net/usb/smsc75xx.c:1460
  [<ffffffff82b5b2e6>] usbnet_probe+0x3b6/0xc30 drivers/net/usb/usbnet.c:1728

Fixes: d0cad871 ("smsc75xx: SMSC LAN75xx USB gigabit ethernet adapter driver")
Cc: stable@kernel.vger.org
Reported-and-tested-by: syzbot+b558506ba8165425fee2@syzkaller.appspotmail.com
Signed-off-by: NPavel Skripkin <paskripkin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/usb/smsc75xx.c

@@ -1483,7 +1483,7 @@ static int smsc75xx_bind(struct usbnet *dev, struct usb_interface *intf)
 	ret = smsc75xx_wait_ready(dev, 0);
 	if (ret < 0) {
 		netdev_warn(dev->net, "device not ready in smsc75xx_bind\n");
-		return ret;
+		goto err;
 	}
 
 	smsc75xx_init_mac_address(dev);
@@ -1492,7 +1492,7 @@ static int smsc75xx_bind(struct usbnet *dev, struct usb_interface *intf)
 	ret = smsc75xx_reset(dev);
 	if (ret < 0) {
 		netdev_warn(dev->net, "smsc75xx_reset error %d\n", ret);
-		return ret;
+		goto err;
 	}
 
 	dev->net->netdev_ops = &smsc75xx_netdev_ops;
@@ -1502,6 +1502,10 @@ static int smsc75xx_bind(struct usbnet *dev, struct usb_interface *intf)
 	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
 	dev->net->max_mtu = MAX_SINGLE_PACKET_SIZE;
 	return 0;
+
+err:
+	kfree(pdata);
+	return ret;
 }
 
 static void smsc75xx_unbind(struct usbnet *dev, struct usb_interface *intf)