binman: Allow listing the entries in an image

It is useful to be able to summarise all the entries in an image, e.g. to
display this to this user. Add a new ListEntries() method to Entry, and
set up a way to call it through the Image class.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/test/127_list.dts b/tools/binman/test/127_list.dts
new file mode 100644
index 0000000..c1d6fce
--- /dev/null
+++ b/tools/binman/test/127_list.dts
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		u-boot {
+		};
+		section {
+			align = <0x100>;
+			cbfs {
+				size = <0x400>;
+				u-boot {
+					cbfs-type = "raw";
+					cbfs-offset = <0x38>;
+				};
+				u-boot-dtb {
+					type = "text";
+					text = "compress xxxxxxxxxxxxxxxxxxxxxx data";
+					cbfs-type = "raw";
+					cbfs-compress = "lzma";
+					cbfs-offset = <0x78>;
+				};
+			};
+			u-boot-dtb {
+				compress = "lz4";
+			};
+		};
+	};
+};