x86: Change condition for using CAR

At present we assume that CAR (Cache-as-RAM) is used if HOBs (Hand-off
blocks) are not, since HOBs typically indicate that an FSP is in use, and
FSPs handle the CAR init.

However this is a bit indirect, and for FSP2 machines which use their own
CAR implementation (such as apollolake) but use the FSP for other
functions, the logic is wrong.

To fix this, add a dedicated Kconfig option to indicate when CAR is used.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: fix a typo in the commit message]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
index 3c9bdf2..9b76394 100644
--- a/arch/x86/cpu/start.S
+++ b/arch/x86/cpu/start.S
@@ -90,7 +90,7 @@
 	jmp	car_init
 .globl car_init_ret
 car_init_ret:
-#ifndef CONFIG_USE_HOB
+#ifdef CONFIG_USE_CAR
 	/*
 	 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
 	 * or fully initialised SDRAM - we really don't care which)
@@ -130,7 +130,7 @@
 
 	/* Get address of global_data */
 	mov	%fs:0, %edx
-#ifdef CONFIG_USE_HOB
+#if defined(CONFIG_USE_HOB) && !defined(CONFIG_USE_CAR)
 	/* Store the HOB list if we have one */
 	test	%esi, %esi
 	jz	skip_hob