rtph265depay: minor clean-up
rtph265depay: minor clean-up

Declutter caps update code a bit.

StreamUtils/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,StreamUtils/gst-plugins-good,StreamUtils/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,GrokImageCompression/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good