forcedeth: fix NAPI rx poll function

fix the forcedeth NAPI poll function to not emit this warning:

[  186.635916] WARNING: at net/core/dev.c:2166 net_rx_action()
[  186.641351]  [<c060d9f5>] net_rx_action+0x145/0x1b0
[  186.646191]  [<c011d752>] __do_softirq+0x42/0x90
[  186.650784]  [<c011d7c6>] do_softirq+0x26/0x30
[  186.655202]  [<c011db48>] local_bh_enable+0x48/0xa0
[  186.660055]  [<c06023e0>] lock_sock_nested+0xa0/0xc0
[  186.664995]  [<c065da16>] tcp_recvmsg+0x16/0xbc0
[  186.669588]  [<c013e94b>] __generic_file_aio_write_nolock+0x27b/0x520
[  186.676001]  [<c0601d75>] sock_common_recvmsg+0x45/0x70
[  186.681202]  [<c05ff5df>] sock_aio_read+0x11f/0x140
[  186.686054]  [<c015c086>] do_sync_read+0xc6/0x110
[  186.690735]  [<c012b9b0>] autoremove_wake_function+0x0/0x40
[  186.696280]  [<c060dcfc>] net_tx_action+0x3c/0xe0
[  186.700961]  [<c015c9c2>] vfs_read+0x132/0x140
[  186.705378]  [<c015cd41>] sys_read+0x41/0x70
[  186.709625]  [<c0102b66>] sysenter_past_esp+0x5f/0x89
[  186.714651]  =======================
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

drivers/net/forcedeth.c

@@ -2268,13 +2268,13 @@ static int nv_rx_process(struct net_device *dev, int limit)
 {
 	struct fe_priv *np = netdev_priv(dev);
 	u32 flags;
-	u32 rx_processed_cnt = 0;
+	int rx_work = 0;
 	struct sk_buff *skb;
 	int len;
 
 	while((np->get_rx.orig != np->put_rx.orig) &&
 	      !((flags = le32_to_cpu(np->get_rx.orig->flaglen)) & NV_RX_AVAIL) &&
-		(rx_processed_cnt++ < limit)) {
+		(rx_work < limit)) {
 
 		dprintk(KERN_DEBUG "%s: nv_rx_process: flags 0x%x.\n",
 					dev->name, flags);
@@ -2396,9 +2396,11 @@ static int nv_rx_process(struct net_device *dev, int limit)
 			np->get_rx.orig = np->first_rx.orig;
 		if (unlikely(np->get_rx_ctx++ == np->last_rx_ctx))
 			np->get_rx_ctx = np->first_rx_ctx;
+
+		rx_work++;
 	}
 
-	return rx_processed_cnt;
+	return rx_work;
 }
 
 static int nv_rx_process_optimized(struct net_device *dev, int limit)