dwc_eth_qos: do not clear pause flags from phy_device->supported

phy_device->supported is originally set by the PHY driver.
The ethernet driver should filter phy_device->supported to only contain
flags supported by the IP.
The IP supports setting rx and tx flow control independently,
therefore SUPPORTED_Pause and SUPPORTED_Asym_Pause should not be cleared.
If the flags are cleared, pause frames cannot be enabled (even if they
are supported by the PHY).
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
Acked-by: Lars Persson <larper@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/synopsys/dwc_eth_qos.c

@@ -982,7 +982,8 @@ static int dwceqos_mii_probe(struct net_device *ndev)
 	if (netif_msg_probe(lp))
 		phy_attached_info(phydev);
 
-	phydev->supported &= PHY_GBIT_FEATURES;
+	phydev->supported &= PHY_GBIT_FEATURES | SUPPORTED_Pause |
+			     SUPPORTED_Asym_Pause;
 
 	lp->link    = 0;
 	lp->speed   = 0;