gstv4l2object: why use V4L2_SEL_TGT_COMPOSE_DEFAULT
File: gstreamer1.0-plugins-good/sys/v4l2/gstv4l2object.c Function: gst_v4l2_object_acquire_format when use VIDIOC_G_SELECTION ioctl, why use sel.target = V4L2_SEL_TGT_COMPOSE_DEFAULT if it is for crop, can we use V4L2_SEL_TGT_CROP ?