BUG: headers with BUG/BUG_ON etc. need linux/bug.h

If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
other BUG variant in a static inline (i.e. not in a #define) then
that header really should be including <linux/bug.h> and not just
expecting it to be implicitly present.

We can make this change risk-free, since if the files using these
headers didn't have exposure to linux/bug.h already, they would have
been causing compile failures/warnings.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 9aaf5bf..ac9586d 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -1,10 +1,12 @@
 #ifndef _LINUX_SCATTERLIST_H
 #define _LINUX_SCATTERLIST_H
 
+#include <linux/string.h>
+#include <linux/bug.h>
+#include <linux/mm.h>
+
 #include <asm/types.h>
 #include <asm/scatterlist.h>
-#include <linux/mm.h>
-#include <linux/string.h>
 #include <asm/io.h>
 
 struct sg_table {