yam: fix possible memory leak in yam_init_driver

If register_netdev(dev) fails, free_netdev(dev) needs
to be called, otherwise a memory leak will occur.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWang Hai <wanghai38@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hamradio/yam.c

@@ -1133,6 +1133,7 @@ static int __init yam_init_driver(void)
 		err = register_netdev(dev);
 		if (err) {
 			printk(KERN_WARNING "yam: cannot register net device %s\n", dev->name);
+			free_netdev(dev);
 			goto error;
 		}
 		yam_devs[i] = dev;