net/wan/fsl_ucc_hdlc: allow ucc index up to 7

There is a need to allow higher indexes to be
able to support MPC83xx platforms. (UCC1-UCC8)
Signed-off-by: NDavid Gounaris <david.gounaris@infinera.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/wan/fsl_ucc_hdlc.c

@@ -1015,7 +1015,7 @@ static int ucc_hdlc_probe(struct platform_device *pdev)
 	}
 
 	ucc_num = val - 1;
-	if ((ucc_num > 3) || (ucc_num < 0)) {
+	if (ucc_num > (UCC_MAX_NUM - 1) || ucc_num < 0) {
 		dev_err(&pdev->dev, ": Invalid UCC num\n");
 		return -EINVAL;
 	}