net: ethernet: Add helper for MACs which support asym pause

Rather than have the MAC drivers manipulate phydev members to indicate
they support Asym Pause, add a helper function.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index ed6c76d..3f319ee 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -1079,8 +1079,7 @@ static int ftgmac100_mii_probe(struct ftgmac100 *priv, phy_interface_t intf)
 	/* Indicate that we support PAUSE frames (see comment in
 	 * Documentation/networking/phy.txt)
 	 */
-	phydev->supported |= SUPPORTED_Pause | SUPPORTED_Asym_Pause;
-	phydev->advertising = phydev->supported;
+	phy_support_asym_pause(phydev);
 
 	/* Display what we found */
 	phy_attached_info(phydev);