timestamps intel: Move timestamp scratchpad to chipset

This retrieves back the value stored with store_initial_timestamp()
in the bootblock for southbridge.

Change-Id: I377c823706c33ed65af023d20d2e4323edd31199
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3908
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/cpu/intel/haswell/romstage.c

@@ -204,10 +204,7 @@ void romstage_common(const struct romstage_params *params)
 	tsc_t start_romstage_time;
 	tsc_t before_dram_time;
 	tsc_t after_dram_time;
-	tsc_t base_time = {
-		.lo = pci_read_config32(PCI_DEV(0, 0x00, 0), 0xdc),
-		.hi = pci_read_config32(PCI_DEV(0, 0x1f, 2), 0xd0)
-	};
+	tsc_t base_time = get_initial_timestamp();
 #endif
 
 #if CONFIG_COLLECT_TIMESTAMPS