smsc75xx: replace 0xffff with PHY_INT_SRC_CLEAR_ALL

This patch defines PHY_INT_SRC_CLEAR_ALL to replace the value 0xffff
in order to be more self-documenting.

This patch should make no functional change, it is purely cosmetic.

Signed-off-by: Steve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index 00103a8..ecab87b 100644
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -511,7 +511,8 @@
 	/* read and write to clear phy interrupt status */
 	ret = smsc75xx_mdio_read(dev->net, mii->phy_id, PHY_INT_SRC);
 	check_warn_return(ret, "Error reading PHY_INT_SRC");
-	smsc75xx_mdio_write(dev->net, mii->phy_id, PHY_INT_SRC, 0xffff);
+	smsc75xx_mdio_write(dev->net, mii->phy_id, PHY_INT_SRC,
+		PHY_INT_SRC_CLEAR_ALL);
 
 	ret = smsc75xx_write_reg(dev, INT_STS, INT_STS_CLEAR_ALL);
 	check_warn_return(ret, "Error writing INT_STS");