rtpmp2tpay: fix up template caps so we can output the default pt 33
rtpmp2tpay: fix up template caps so we can output the default pt 33

Add fixed payload type for mp2t to template caps as well, so
our output caps match the advertised default pt. Fixes a
regression from 1.2.

There's still something wrong with caps negotiation though,
rtpmp2tpay payload=96 ! fakesink will not output caps with
payload=96.

vatavuserban/gst-plugins-good,vatavuserban/gst-plugins-good,surround-io/gst-plugins-good,vatavuserban/gst-plugins-good,ndufresne/gst-plugins-good,wkatsak/gst-plugins-good,jpakkane/gstreamer-plugins-good,wkatsak/gst-plugins-good,surround-io/gst-plugins-good,ndufresne/gst-plugins-good,vatavuserban/gst-plugins-good,jpakkane/gstreamer-plugins-good,surround-io/gst-plugins-good,ndufresne/gst-plugins-good,wkatsak/gst-plugins-good,jpakkane/gstreamer-plugins-good,jpakkane/gstreamer-plugins-good,wkatsak/gst-plugins-good,ndufresne/gst-plugins-good,surround-io/gst-plugins-good