test: py: vboot: add test for global image signature

Adds test units for the pre-load header signature.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>

test/py/tests/vboot/simple-images.its

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	description = "Chrome OS kernel image with one or more FDT blobs";
+	#address-cells = <1>;
+
+	images {
+		kernel {
+			data = /incbin/("test-kernel.bin");
+			type = "kernel_noload";
+			arch = "sandbox";
+			os = "linux";
+			compression = "none";
+			load = <0x4>;
+			entry = <0x8>;
+			kernel-version = <1>;
+		};
+		fdt-1 {
+			description = "snow";
+			data = /incbin/("sandbox-kernel.dtb");
+			type = "flat_dt";
+			arch = "sandbox";
+			compression = "none";
+			fdt-version = <1>;
+		};
+	};
+	configurations {
+		default = "conf-1";
+		conf-1 {
+			kernel = "kernel";
+			fdt = "fdt-1";
+		};
+	};
+};