ipv4: Adjust in_dev handling in fib_validate_source()

Checking for in_dev being NULL is pointless.

In fact, all of our callers have in_dev precomputed already,
so just pass it in and remove the NULL checking.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 9e6c26d..619f68a 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -233,7 +233,7 @@
 extern __be32 fib_compute_spec_dst(struct sk_buff *skb);
 extern int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 			       u8 tos, int oif, struct net_device *dev,
-			       u32 *itag);
+			       struct in_device *idev, u32 *itag);
 extern void fib_select_default(struct fib_result *res);
 
 /* Exported by fib_semantics.c */