mboxd: Rename flash files

Change-Id: Icfe9d61775a198c5a0f8227bf5d6c4b7f11aeec3
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/test/mbox.c b/test/mbox.c
index 3daf493..7e03292 100644
--- a/test/mbox.c
+++ b/test/mbox.c
@@ -14,7 +14,7 @@
 #include <unistd.h>
 
 #include "mbox.h"
-#include "mboxd_flash.h"
+#include "flash.h"
 #include "mboxd_lpc.h"
 #include "mboxd_msg.h"
 #include "mboxd_windows.h"