layout: Tidy up the include-args API

Move all forward declarations into `layout.h`, use consistent naming.

Change-Id: I0e87c9d91b9bc4d78f9cee98caff6985803f7be7
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54287
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

cli_classic.c

@@ -857,7 +857,7 @@ out:
 		free(flashes[i].chip);
 	}
 
-	layout_cleanup(&include_args);
+	cleanup_include_args(&include_args);
 	free(filename);
 	free(fmapfile);
 	free(referencefile);