net/9p/trans_virtio.c: Use BUG_ON

if (...) BUG(); should be replaced with BUG_ON(...) when the test has no
side-effects to allow a definition of BUG_ON that drops the code completely.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@ disable unlikely @ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (unlikely(E)) { BUG(); }
+ BUG_ON(E);
)

@@ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (E) { BUG(); }
+ BUG_ON(E);
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/9p/trans_virtio.c

@@ -183,8 +183,7 @@ pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
 		sg_set_buf(&sg[index++], data, s);
 		count -= s;
 		data += s;
-		if (index > limit)
-			BUG();
+		BUG_ON(index > limit);
 	}
 
 	return index-start;