Misc: Use acpi_is_wakeup_s3()

Change-Id: I46906e6d68775edc5cfe199cfeb465db4da2691f
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/6072
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/cpu/x86/smm/backup_default_smm.c

@@ -45,7 +45,7 @@ void *backup_default_smm_area(void)
 	}
 
 	/* Only back up the area on S3 resume. */
-	if (acpi_slp_type == 3) {
+	if (acpi_is_wakeup_s3()) {
 		memcpy(save_area, default_smm, SMM_DEFAULT_SIZE);
 		return save_area;
 	}