x86: apl: Check low-level init in FSP-S pre-init

If U-Boot is not running FSP-S it should not do the pre-init either. Add a
condition to handle this.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/apollolake/fsp_s.c

@@ -157,6 +157,8 @@ int arch_fsps_preinit(void)
 	struct udevice *itss;
 	int ret;
 
+	if (!ll_boot_init())
+		return 0;
 	ret = irq_first_device_type(X86_IRQT_ITSS, &itss);
 	if (ret)
 		return log_msg_ret("no itss", ret);