common: Drop linux/stringify.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/gdsys/common/osd.c b/board/gdsys/common/osd.c
index cda0cc6..679f8f3 100644
--- a/board/gdsys/common/osd.c
+++ b/board/gdsys/common/osd.c
@@ -10,6 +10,7 @@
 #include <command.h>
 #include <i2c.h>
 #include <malloc.h>
+#include <linux/stringify.h>
 
 #include "ch7301.h"
 #include "dp501.h"