tools: binman: add support for pre-load header

Adds the support of the pre-load header with the image signature
to binman.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/tools/binman/test/227_pre_load_pss.dts b/tools/binman/test/227_pre_load_pss.dts
new file mode 100644
index 0000000..b1b01d5
--- /dev/null
+++ b/tools/binman/test/227_pre_load_pss.dts
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		pre-load {
+			content = <&image>;
+			 algo-name = "sha256,rsa2048";
+			 padding-name = "pss";
+			 key-name = "tools/binman/test/225_dev.key";
+			 header-size = <4096>;
+			 version = <0x11223344>;
+		};
+
+		image: blob-ext {
+			filename = "refcode.bin";
+		};
+	};
+};