net: Refactor full duplex flow control resolution

These 4 drivers have identical full duplex flow control resolution
functions.  This patch changes them all to use one common function.

The function in question decides whether a device should enable TX and
RX flow control in a standard way (IEEE 802.3-2005 table 28B-3), so this
should also be useful for other drivers.

Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index ee2eac3..fed22ff 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -435,28 +435,6 @@
 	smsc95xx_write_reg_async(dev, MAC_CR, &pdata->mac_cr);
 }
 
-static u8 smsc95xx_resolve_flowctrl_fulldplx(u16 lcladv, u16 rmtadv)
-{
-	u8 cap = 0;
-
-	if (lcladv & ADVERTISE_PAUSE_CAP) {
-		if (lcladv & ADVERTISE_PAUSE_ASYM) {
-			if (rmtadv & LPA_PAUSE_CAP)
-				cap = FLOW_CTRL_TX | FLOW_CTRL_RX;
-			else if (rmtadv & LPA_PAUSE_ASYM)
-				cap = FLOW_CTRL_RX;
-		} else {
-			if (rmtadv & LPA_PAUSE_CAP)
-				cap = FLOW_CTRL_TX | FLOW_CTRL_RX;
-		}
-	} else if (lcladv & ADVERTISE_PAUSE_ASYM) {
-		if ((rmtadv & LPA_PAUSE_CAP) && (rmtadv & LPA_PAUSE_ASYM))
-			cap = FLOW_CTRL_TX;
-	}
-
-	return cap;
-}
-
 static void smsc95xx_phy_update_flowcontrol(struct usbnet *dev, u8 duplex,
 					    u16 lcladv, u16 rmtadv)
 {
@@ -469,7 +447,7 @@
 	}
 
 	if (duplex == DUPLEX_FULL) {
-		u8 cap = smsc95xx_resolve_flowctrl_fulldplx(lcladv, rmtadv);
+		u8 cap = mii_resolve_flowctrl_fdx(lcladv, rmtadv);
 
 		if (cap & FLOW_CTRL_RX)
 			flow = 0xFFFF0002;