x86: baytrail: Support operation as an EFI payload

Disable a few things which interfere with the EFI init. This allows the
Minnowboard MAX to boot into EFI, load a U-Boot payload then boot to the
U-Boot prompt.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/baytrail/cpu.c b/arch/x86/cpu/baytrail/cpu.c
index a011730..b1faf8c 100644
--- a/arch/x86/cpu/baytrail/cpu.c
+++ b/arch/x86/cpu/baytrail/cpu.c
@@ -45,6 +45,8 @@
 
 static int cpu_x86_baytrail_probe(struct udevice *dev)
 {
+	if (!ll_boot_init())
+		return 0;
 	debug("Init BayTrail core\n");
 
 	/*