net: atm: clean up a range check

The code works fine but the problem is that check for negatives is a
no-op:

	if (arg < 0)
		i = 0;

The "i" value isn't used.  We immediately overwrite it with:

	i = array_index_nospec(arg, MAX_LEC_ITF);

The array_index_nospec() macro returns zero if "arg" is out of bounds so
this works, but the dead code is confusing and it doesn't look very
intentional.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/atm/lec.c

@@ -726,9 +726,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg)
 	struct lec_priv *priv;
 
 	if (arg < 0)
-		i = 0;
-	else
-		i = arg;
+		arg = 0;
 	if (arg >= MAX_LEC_ITF)
 		return -EINVAL;
 	i = array_index_nospec(arg, MAX_LEC_ITF);