flow_dissector: clean up IPIP case

Explicitly set proto to ETH_P_IP and jump directly to ip processing.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 00ee068..3259446 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -139,7 +139,8 @@
 		break;
 	}
 	case IPPROTO_IPIP:
-		goto again;
+		proto = htons(ETH_P_IP);
+		goto ip;
 	default:
 		break;
 	}