binman: Add support for building x86 ROMs with SPL

When building for 64-bit x86 we need an SPL binary in the ROM. Add support
for this. Also increase entry test code coverage to 100%.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/tools/binman/test/37_x86_no_ucode.dts b/tools/binman/test/37_x86_no_ucode.dts
new file mode 100644
index 0000000..9e12156
--- /dev/null
+++ b/tools/binman/test/37_x86_no_ucode.dts
@@ -0,0 +1,20 @@
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		sort-by-pos;
+		end-at-4gb;
+		size = <0x200>;
+		u-boot-with-ucode-ptr {
+		};
+
+		u-boot-dtb-with-ucode {
+		};
+
+		u-boot-ucode {
+		};
+	};
+};