niu: timeout ignored in tcam_wait_bit()

With `while (--limit > 0)' i reaches 0 after the loop, so upon timeout the
error was not returned.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/niu.c

@@ -2844,7 +2844,7 @@ static int tcam_wait_bit(struct niu *np, u64 bit)
 			break;
 		udelay(1);
 	}
-	if (limit < 0)
+	if (limit <= 0)
 		return -ENODEV;
 
 	return 0;