BUG_ON cleanups in arch/i386

This changes a couple of if() BUG(); constructs to
BUG_ON(); so it can be safely optimized away.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/arch/i386/mm/discontig.c b/arch/i386/mm/discontig.c
index 51e3739..455597d 100644
--- a/arch/i386/mm/discontig.c
+++ b/arch/i386/mm/discontig.c
@@ -153,8 +153,7 @@
 	 */
 	if (node_start_pfn[nid] > max_pfn)
 		node_start_pfn[nid] = max_pfn;
-	if (node_start_pfn[nid] > node_end_pfn[nid])
-		BUG();
+	BUG_ON(node_start_pfn[nid] > node_end_pfn[nid]);
 }
 
 /*