common: Move bootcount functions to their header file

These don't need to be in common.h so move them out.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/board/BuR/brppt1/board.c b/board/BuR/brppt1/board.c
index ef4f5c9..e0d1707 100644
--- a/board/BuR/brppt1/board.c
+++ b/board/BuR/brppt1/board.c
@@ -10,6 +10,7 @@
  */
 
 #include <common.h>
+#include <bootcount.h>
 #include <env.h>
 #include <errno.h>
 #include <spl.h>