Add more information to the cbfstool print

Show what's in a stage or payload. This will let people better understand
what's in a stage or payload.

Change-Id: If6d9a877b4aedd5cece76774e41f0daadb20c008
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/2176
Tested-by: build bot (Jenkins)

util/cbfstool/cbfs.h

@@ -106,6 +106,8 @@ struct cbfs_payload {
 #define CBFS_COMPONENT_NULL 0xFFFFFFFF
 
 int cbfs_file_header(unsigned long physaddr);
+#define CBFS_SUBHEADER(_p) ( (void *) ((((uint8_t *) (_p)) + ntohl((_p)->offset))) )
+
 struct cbfs_file *cbfs_create_empty_file(uint32_t physaddr, uint32_t size);
 
 #endif