BUG_ON() Conversion in fs/exec.c

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

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

fs/exec.c

@@ -561,7 +561,7 @@ static int exec_mmap(struct mm_struct *mm)
 	arch_pick_mmap_layout(mm);
 	if (old_mm) {
 		up_read(&old_mm->mmap_sem);
-		if (active_mm != old_mm) BUG();
+		BUG_ON(active_mm != old_mm);
 		mmput(old_mm);
 		return 0;
 	}