x86: chromebook_panther: Correct the image layout

This board does not have microcode but at present that is not supported
by Kconfig nor the binman image layout. Fix both of these.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/Kconfig

@@ -594,8 +594,13 @@ config HAVE_REFCODE
           Various peripherals may fail to work.
 
 config HAVE_MICROCODE
-	bool
+	bool "Board requires a microcode binary"
 	default y if !FSP_VERSION2
+	help
+	  Enable this if the board requires microcode to be loaded on boot.
+	  Typically this is handed by the FSP for modern boards, but for
+	  some older boards, it must be programmed by U-Boot, and that form
+	  part of the image.
 
 config SMP
 	bool "Enable Symmetric Multiprocessing"

arch/x86/dts/u-boot.dtsi

@@ -75,11 +75,15 @@
 	u-boot {
 		offset = <CONFIG_SYS_TEXT_BASE>;
 	};
-# else
+# elif defined(CONFIG_HAVE_MICROCODE)
 	/* If there is no SPL then we need to put microcode in U-Boot */
 	u-boot-with-ucode-ptr {
 		offset = <CONFIG_X86_OFFSET_U_BOOT>;
 	};
+# else
+	u-boot-nodtb {
+		offset = <CONFIG_X86_OFFSET_U_BOOT>;
+	};
 # endif
 #endif
 #ifdef CONFIG_HAVE_MICROCODE

configs/chromebox_panther_defconfig

@@ -8,7 +8,9 @@ CONFIG_DEFAULT_DEVICE_TREE="chromebox_panther"
 CONFIG_VENDOR_GOOGLE=y
 CONFIG_TARGET_CHROMEBOX_PANTHER=y
 CONFIG_HAVE_MRC=y
+# CONFIG_HAVE_MICROCODE is not set
 CONFIG_HAVE_VGA_BIOS=y
+CONFIG_X86_OFFSET_U_BOOT=0xffa00000
 CONFIG_FIT=y
 CONFIG_BOOTSTAGE=y
 CONFIG_BOOTSTAGE_REPORT=y