bridge: eliminate call by reference

Change the bridging hook to be simple function with return value
rather than modifying the skb argument. This could generate better
code and is cleaner.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index fd1b6eb..4ff211d 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -105,7 +105,8 @@
 #include <linux/netdevice.h>
 
 extern void brioctl_set(int (*ioctl_hook)(unsigned int, void __user *));
-extern int (*br_handle_frame_hook)(struct net_bridge_port *p, struct sk_buff **pskb);
+extern struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
+					       struct sk_buff *skb);
 extern int (*br_should_route_hook)(struct sk_buff **pskb);
 
 #endif