va: h264enc: set the reconf flag when cpb_size updated

This feature can be changed dynamically in playing state, so we
need to set reconf flag to trigger reconfig.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6471>

subprojects/gst-plugins-bad/sys/va/gstvah264enc.c

@@ -3386,6 +3386,7 @@ gst_va_h264_enc_set_property (GObject * object, guint prop_id,
       break;
     case PROP_CPB_SIZE:
       self->prop.cpb_size = g_value_get_uint (value);
+      g_atomic_int_set (&GST_VA_BASE_ENC (self)->reconf, TRUE);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);