BUG_ON() Conversion in mm/swap_state.c

this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/mm/swap_state.c b/mm/swap_state.c
index d7af296..e0e1583 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -148,8 +148,7 @@
 	swp_entry_t entry;
 	int err;
 
-	if (!PageLocked(page))
-		BUG();
+	BUG_ON(!PageLocked(page));
 
 	for (;;) {
 		entry = get_swap_page();