controller: add the missing abi padding

While this technically is an abi break, we decided to do this:
1) the struct is documented to be internal
2) the struct is alloced and freed inside the library
3) there are no public methods that receive or return instances
4) the only code known to use this struct are classes containd here

1 files changed, 2 insertions, 2 deletions

diff --git a/libs/gst/controller/gsttimedvaluecontrolsource.h b/libs/gst/controller/gsttimedvaluecontrolsource.h
index 7bc901e9e..d161ecbf8 100644
--- a/libs/gst/controller/gsttimedvaluecontrolsource.h
+++ b/libs/gst/controller/gsttimedvaluecontrolsource.h
@@ -55,7 +55,7 @@ typedef struct _GstControlPoint GstControlPoint;
  * @timestamp: timestamp of the value change
  * @value: the new value
  *
- * a internal structure for value+time and various temporary
+ * An internal structure for value+time and various temporary
  * values used for interpolation. This "inherits" from
  * GstTimedValue.
  */
@@ -77,8 +77,8 @@ struct _GstControlPoint
     struct {
       gdouble c1s, c2s, c3s;
     } cubic_mono;
+    gpointer _gst_reserved[GST_PADDING];
   } cache;
-
 };
 
 GType gst_control_point_get_type (void);