smsc75xx: eliminate unnecessary phy register read

Only a write is necessary to clear the interrupt status, and we
don't use the value from the preceding read operation.  This
patch eliminates the unnecessary read.
Signed-off-by: NSteve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/usb/smsc75xx.c

@@ -508,9 +508,7 @@ static int smsc75xx_link_reset(struct usbnet *dev)
 	u16 lcladv, rmtadv;
 	int ret;
 
-	/* 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");
+	/* write to clear phy interrupt status */
 	smsc75xx_mdio_write(dev->net, mii->phy_id, PHY_INT_SRC,
 		PHY_INT_SRC_CLEAR_ALL);