media: Documentation: Document new v4l2_ctrl_handler_free() behaviour

v4l2_ctrl_handler_free() no longer resets the handler's error code.
Document it.

Signed-off-by: Sakari Ailus <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Hans Verkuil <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

Documentation/driver-api/media/v4l2-controls.rst

···
 
 	v4l2_ctrl_handler_free(&foo->ctrl_handler);
 
+:c:func:`v4l2_ctrl_handler_free` does not touch the handler's ``error`` field.
 
 2) Add controls:
 
···
 			V4L2_CID_TEST_PATTERN, ARRAY_SIZE(test_pattern) - 1, 0,
 			0, test_pattern);
 	...
-	if (foo->ctrl_handler.error) {
-		int err = foo->ctrl_handler.error;
-
-		v4l2_ctrl_handler_free(&foo->ctrl_handler);
-		return err;
-	}
+	if (foo->ctrl_handler.error)
+		return v4l2_ctrl_handler_free(&foo->ctrl_handler);
 
 The :c:func:`v4l2_ctrl_new_std` function returns the v4l2_ctrl pointer to
 the new control, but if you do not need to access the pointer outside the