netpoll: Add netpoll_rx_processing

Add a helper netpoll_rx_processing that reports when netpoll has
receive side processing to perform.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 2ad330e..ef83a25 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -538,7 +538,7 @@
 	int hlen, tlen;
 	int hits = 0, proto;
 
-	if (list_empty(&npinfo->rx_np))
+	if (!netpoll_rx_processing(npinfo))
 		return;
 
 	/* Before checking the packet, we do some early
@@ -770,7 +770,7 @@
 	struct netpoll *np, *tmp;
 	uint16_t source;
 
-	if (list_empty(&npinfo->rx_np))
+	if (!netpoll_rx_processing(npinfo))
 		goto out;
 
 	if (skb->dev->type != ARPHRD_ETHER)