utils: codegen: gen-controls.py: Move helper classes to separate file

The ControlEnum and Control helper classes defined in gen-controls.py
are useful for other generator scripts. Move them to a separate file to
make it possible to share them.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>

include/libcamera/meson.build

@@ -88,6 +88,7 @@ foreach mode, entry : controls_map
                                      command : [gen_controls, '-o', '@OUTPUT@',
                                                 '--mode', mode, '-t', template_file,
                                                 '-r', ranges_file, '@INPUT@'],
+                                     env : py_build_env,
                                      install : true,
                                      install_dir : libcamera_headers_install_dir)
 endforeach