common: Drop bootstage.h from common header

Move this fairly uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arc/lib/bootm.c b/arch/arc/lib/bootm.c
index d38c18e..1b08ffe 100644
--- a/arch/arc/lib/bootm.c
+++ b/arch/arc/lib/bootm.c
@@ -3,9 +3,10 @@
  * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
  */
 
+#include <common.h>
+#include <bootstage.h>
 #include <irq_func.h>
 #include <asm/cache.h>
-#include <common.h>
 
 DECLARE_GLOBAL_DATA_PTR;