gdkpixbufdec: always output a TIME segment
It makes no sense for a decoder to output a BYTES segment, and many elements one would plug downstream of a video decoder assume the segments they receive are in TIME format, for example this fixes:
gst-validate-1.0 filesrc location=opacity01.svg ! gdkpixbufdec !
videobalance ! videoconvert ! fakesink
In that case, videobalance was emitting an assertion when trying to call gst_object_sync_values()