show RTP TX/RX stats in 'mgcp show stats' output

Make the 'mgcp show stats' VTY command display TX/RX counters
for an RTP stream. This command was already showing the counter
for dropped packets from the same counter group, so it seems
natural to display other relevant counters in the group as well.

Change-Id: I1313e64d7d8b49964f21fc8d213cba6c9fb6c7cf
Related: OS#2660
1 file changed