cbmem: add vboot cmbem id

The vboot firmware selection from romstage will need to
pass the resulting vboot data to other consumers. This will
be done using a cbmem entry.

Change-Id: I497caba53f9f3944513382f3929d21b04bf3ba9e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2851
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/include/cbmem.h

@@ -67,6 +67,7 @@
 #define CBMEM_ID_RAMSTAGE	0x9a357a9e
 #define CBMEM_ID_RAMSTAGE_CACHE	0x9a3ca54e
 #define CBMEM_ID_ROOT		0xff4007ff
+#define CBMEM_ID_VBOOT_HANDOFF	0x780074f0
 #define CBMEM_ID_NONE		0x00000000
 
 #ifndef __ASSEMBLER__