x86: Add an option to control the position of SPL

For Apollo Lake SPL is run from CAR (cache-as-RAM) which is in a different
location from where SPL must be placed in ROM. In other words, although
SPL runs before SDRAM is set up, it is not execute-in-place (XIP).

Add a Kconfig option for the ROM position.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/dts/u-boot.dtsi b/arch/x86/dts/u-boot.dtsi
index d84c648..fad3e7c 100644
--- a/arch/x86/dts/u-boot.dtsi
+++ b/arch/x86/dts/u-boot.dtsi
@@ -45,7 +45,7 @@
 	};
 #endif
 	u-boot-spl {
-		offset = <CONFIG_SPL_TEXT_BASE>;
+		offset = <CONFIG_X86_OFFSET_SPL>;
 	};
 	u-boot-spl-dtb {
 	};
@@ -54,7 +54,7 @@
 	};
 #elif defined(CONFIG_SPL)
 	u-boot-spl-with-ucode-ptr {
-		offset = <CONFIG_SPL_TEXT_BASE>;
+		offset = <CONFIG_X86_OFFSET_SPL>;
 	};
 	u-boot-dtb-with-ucode2 {
 		type = "u-boot-dtb-with-ucode";