net: unix: remove redundant assignment to variable 'err'

After commit 37ab4fa7 ("net: unix: allow bind to fail on mutex lock"),
the assignment to err is redundant. So remove it.
Signed-off-by: NJing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/unix/af_unix.c

@@ -878,7 +878,6 @@ static int unix_autobind(struct socket *sock)
 	if (err)
 		return err;
 
-	err = 0;
 	if (u->addr)
 		goto out;