ipv6: Use BUG_ON

The semantic patch that makes this transformation is as follows:

// <smpl>
@@ expression e; @@
-if (e) BUG();
+BUG_ON(e);
// </smpl>
Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_output.c

@@ -801,8 +801,8 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 		/*
 		 *	Copy a block of the IP datagram.
 		 */
-		if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
-			BUG();
+		BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
+				     len));
 		left -= len;
 
 		fh->frag_off = htons(offset);