x86: baytrail: Support running as an EFI payload

We should not fiddle with interrupts or the FSP when running as an EFI
payload. Detect this and skip this code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/baytrail/valleyview.c b/arch/x86/cpu/baytrail/valleyview.c
index 2d5a0eb..6c3dfe8 100644
--- a/arch/x86/cpu/baytrail/valleyview.c
+++ b/arch/x86/cpu/baytrail/valleyview.c
@@ -43,6 +43,8 @@
 {
 	int ret;
 
+	if (!ll_boot_init())
+		return 0;
 	ret = pirq_init();
 	if (ret)
 		return ret;