net: phy: phy_support_sym_pause: Clear Asym Pause

When indicating the MAC supports Symmetric Pause, clear the Asymmetric
Pause bit, which could of been already set is the PHY supports it.

Reported-by: Labbe Corentin <clabbe@baylibre.com>
Fixes: c306ad36184f ("net: ethernet: Add helper for MACs which support pause")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy_device.c

@@ -1940,6 +1940,7 @@ EXPORT_SYMBOL(phy_remove_link_mode);
  */
 void phy_support_sym_pause(struct phy_device *phydev)
 {
+	phydev->supported &= ~SUPPORTED_Asym_Pause;
 	phydev->supported |= SUPPORTED_Pause;
 	phydev->advertising = phydev->supported;
 }