i40e: Never let speed get set to 0 in get_settings

In ethtool, there is a possibility of speed getting set to 0
if advertise is set to 0 (which it is when autoneg is disabled).
We never want this to happen as the firmware will actually attempt
to set the speed to 0 sending link down, so add an extra check
to make sure this doesn't happen.

Change-ID: I62e0eeee2cbf043d8e6f5c9c9f0b92794e877f01
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -666,6 +666,13 @@ static int i40e_set_settings(struct net_device *netdev,
 	    advertise & ADVERTISED_40000baseLR4_Full)
 		config.link_speed |= I40E_LINK_SPEED_40GB;
 
+	/* If speed didn't get set, set it to what it currently is.
+	 * This is needed because if advertise is 0 (as it is when autoneg
+	 * is disabled) then speed won't get set.
+	 */
+	if (!config.link_speed)
+		config.link_speed = abilities.link_speed;
+
 	if (change || (abilities.link_speed != config.link_speed)) {
 		/* copy over the rest of the abilities */
 		config.phy_type = abilities.phy_type;