x86: quark: Fix build error for quark-based boards

With the conversion to use binman to build x86 boards, Intel Galileo
board does not build anymore due to missing ucode entry. In fact
ucode is not needed for quark-based boards.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

arch/x86/dts/quark-u-boot.dtsi

+/*
+ * Copyright (C) 2016, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <u-boot.dtsi>
+
+#ifdef CONFIG_ROM_SIZE
+/ {
+	binman {
+		u-boot-with-ucode-ptr {
+			optional-ucode;
+		};
+	};
+};
+#endif