expo: Update tests to include textline

Provide test coverage for the new expo object type, including building
and reading/writing settings.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/boot/files/expo_ids.h

@@ -21,5 +21,8 @@ enum {
 	ID_AC_ON,
 	ID_AC_MEMORY,
 
+	ID_MACHINE_NAME,
+	ID_MACHINE_NAME_EDIT,
+
 	ID_DYNAMIC_START,
 };

test/boot/files/expo_layout.dts

@@ -55,6 +55,14 @@
 				start-bit = <0x422>;
 				bit-length = <2>;
 			};
+
+			machine-name {
+				id = <ID_MACHINE_NAME>;
+				type = "textline";
+				max-chars = <20>;
+				title = "Machine name";
+				edit-id = <ID_MACHINE_NAME_EDIT>;
+			};
 		};
 	};