expo: Split out cedit into its own header

Before adding more functions to this interface, create a new header for
the configuration editor.

Fix up the expo header guard while we are here.

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

include/cedit.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2023 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __CEDIT_H
+#define __CEDIT_H
+
+struct expo;
+struct video_priv;
+
+/**
+ * cedit_arange() - Arrange objects in a configuration-editor scene
+ *
+ * @exp: Expo to update
+ * @vid_priv: Private info of the video device
+ * @scene_id: scene ID to arrange
+ * Returns: 0 if OK, -ve on error
+ */
+int cedit_arange(struct expo *exp, struct video_priv *vid_priv, uint scene_id);
+
+/**
+ * cedit_run() - Run a configuration editor
+ *
+ * This accepts input until the user quits with Escape
+ *
+ * @exp: Expo to use
+ * Returns: 0 if OK, -ve on error
+ */
+int cedit_run(struct expo *exp);
+
+#endif /* __CEDIT_H */