timestamp: add vboot check points

It's desirable to measure the vboot firmware selection time.
Therefore add vboot check points to the timestamp ids.

Change-Id: Ib103a9e91652cf96abcacebf0f211300e03f71fd
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2852
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/include/timestamp.h

@@ -37,6 +37,8 @@ enum timestamp_id {
 	TS_BEFORE_INITRAM = 2,
 	TS_AFTER_INITRAM = 3,
 	TS_END_ROMSTAGE = 4,
+	TS_START_VBOOT = 5,
+	TS_END_VBOOT = 6,
 	TS_START_COPYRAM = 8,
 	TS_END_COPYRAM = 9,
 	TS_START_RAMSTAGE = 10,