Hook up MRC cache update

Requirements:
  - must be in ramstage (locking flash while executing code from there
    might not work)
  - must be after cbmem is reinitialized (so the mrc cache copy of the
    current run can be found)

Change-Id: I8028fb073349ce2b027ef5f8397dc1a1b8b31c02
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/1002
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/include/timestamp.h

@@ -47,6 +47,7 @@ enum timestamp_id {
 	TS_DEVICE_ENABLE = 50,
 	TS_DEVICE_INITIALIZE = 60,
 	TS_DEVICE_DONE = 70,
+	TS_CBMEM_POST = 75,
 	TS_WRITE_TABLES = 80,
 	TS_LOAD_PAYLOAD = 90,
 	TS_ACPI_WAKE_JUMP = 98,