SMSC: timeout reaches -1

With a postfix decrement timeouts will reach -1 rather than 0, so
the error path does not appear.

Signed-off-by: Roel Kluin <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/smsc911x.c

···
 	do {
 		msleep(1);
 		e2cmd = smsc911x_reg_read(pdata, E2P_CMD);
-	} while ((e2cmd & E2P_CMD_EPC_BUSY_) && (timeout--));
+	} while ((e2cmd & E2P_CMD_EPC_BUSY_) && (--timeout));
 
 	if (!timeout) {
 		SMSC_TRACE(DRV, "TIMED OUT");