qlcnic: set mtu lower limit

Setting mtu < 68 is not supported.

Signed-off-by: Sritej Velaga <sritej.velaga@qlogic.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/qlcnic/qlcnic_hw.c b/drivers/net/qlcnic/qlcnic_hw.c
index 712cfab..9d3e16d 100644
--- a/drivers/net/qlcnic/qlcnic_hw.c
+++ b/drivers/net/qlcnic/qlcnic_hw.c
@@ -758,9 +758,9 @@
 	struct qlcnic_adapter *adapter = netdev_priv(netdev);
 	int rc = 0;
 
-	if (mtu > P3_MAX_MTU) {
-		dev_err(&adapter->netdev->dev, "mtu > %d bytes unsupported\n",
-						P3_MAX_MTU);
+	if (mtu < P3_MIN_MTU || mtu > P3_MAX_MTU) {
+		dev_err(&adapter->netdev->dev, "%d bytes < mtu < %d bytes"
+			" not supported\n", P3_MAX_MTU, P3_MIN_MTU);
 		return -EINVAL;
 	}