soc/apollolake/acpi: Fill ACPI HPET table

HPET table is required to report integrated HPET timer to kernel.
Without HPET table added,Linux kernel will panic when loading timer
driver.

Change-Id: I7368bc29f4e03d5882dcfc4a770fa7bfbc6c26a0
Signed-off-by: Zhao, Lijian <lijian.zhao@intel.com>
Reviewed-on: https://review.coreboot.org/13374
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/soc/intel/apollolake/acpi.c

@@ -113,3 +113,10 @@ void soc_fill_common_fadt(acpi_fadt_t * fadt)
 
 	fadt->x_gpe1_blk.space_id = 1;
 }
+
+unsigned long southbridge_write_acpi_tables(device_t device,
+		unsigned long current,
+		struct acpi_rsdp *rsdp)
+{
+	return acpi_write_hpet(device, current, rsdp);
+}