cbfs: add cbfs_serialized.h header file

The serialized format of CBFS is separate from the APIs
used to traverse and read from CBFS. Separate those out
so they can be consumed as a standalone header.

Change-Id: I09f71d9c474ee9f23a62b0062ffa777963d1a4dd
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9125
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/arch/x86/include/arch/cbfs.h

@@ -20,7 +20,10 @@
 #ifndef __INCLUDE_ARCH_CBFS__
 #define __INCLUDE_ARCH_CBFS__
 
-#include <cbfs_core.h>
+#include <arch/byteorder.h>
+#include <cbfs_serialized.h>
+
+#define CBFS_SUBHEADER(_p) ( (void *) ((((uint8_t *) (_p)) + ntohl((_p)->offset))) )
 
 static struct cbfs_file *walkcbfs_head(char *target)
 {