smsc911x: check for FFWD success before checking for timeout

This patch from Juha Leppanen suppresses a false warning if a fast
forward operation succeeds on the very last attempt.

Juha> If smsc911x_reg_read loop is executed 500 times, timeout reaches 0
Juha> and the 500th smsc911x_reg_read result in val is ignored. If
Juha> testing order is changed, then val is checked first. The 500th
Juha> reg_read might be GOOD, why ignore it!
Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/smsc911x.c

@@ -955,7 +955,7 @@ smsc911x_rx_fastforward(struct smsc911x_data *pdata, unsigned int pktbytes)
 		do {
 			udelay(1);
 			val = smsc911x_reg_read(pdata, RX_DP_CTRL);
-		} while (--timeout && (val & RX_DP_CTRL_RX_FFWD_));
+		} while ((val & RX_DP_CTRL_RX_FFWD_) && --timeout);
 
 		if (unlikely(timeout == 0))
 			SMSC_WARNING(HW, "Timed out waiting for "