sb/intel/fspi89xx: Fix timestamp code

The save_timestamp_to_cmos code was used at Sage before the early
cbmem was available.  Update it to use the standard timestamp calls,
based on the rangeley implementation.

Change-Id: I9a3a6609bdc8d03c4b86951daa1cafddd9c1332e
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20564
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/southbridge/intel/fsp_i89xx/romstage.c

@@ -99,9 +99,9 @@ void main(FSP_INFO_HEADER *fsp_info_header)
 
 	post_code(0x40);
 
-#if IS_ENABLED(CONFIG_COLLECT_TIMESTAMPS)
-	save_timestamp_to_cmos(CMOS_MAIN_START_ADDR, rdtsc());
-#endif
+	timestamp_init(get_initial_timestamp());
+	timestamp_add_now(TS_START_ROMSTAGE);
+
 	pch_enable_lpc();
 
 	/* Enable GPIOs */
@@ -151,9 +151,7 @@ void main(FSP_INFO_HEADER *fsp_info_header)
 
 	post_code(0x48);
 
-#if IS_ENABLED(CONFIG_COLLECT_TIMESTAMPS)
-	save_timestamp_to_cmos(CMOS_PRE_INITRAM_ADDR, rdtsc());
-#endif
+	timestamp_add_now(TS_BEFORE_INITRAM);
 
   /*
    * Call early init to initialize memory and chipset. This function returns