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>
diff --git a/arch/x86/dts/u-boot.dtsi b/arch/x86/dts/u-boot.dtsi
index 1e0a985..fa8106c 100644
--- a/arch/x86/dts/u-boot.dtsi
+++ b/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