[NETPOLL]: rx_flags bugfix

Initialize npinfo->rx_flags.  The way it stands now, this will have random
garbage, and so will incur a locking penalty even when an rx_hook isn't
registered and we are not active in the netpoll polling code.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c327c9e..895f3ef 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -639,6 +639,7 @@
 		if (!npinfo)
 			goto release;
 
+		npinfo->rx_flags = 0;
 		npinfo->rx_np = NULL;
 		npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
 		npinfo->poll_owner = -1;