bluez5-device: use correct RTP payload type
THIS IS UNTESTED! If that's a problem, someone needs to test this, but given the nature of the change, what could possibly go wrong? :)
If one device tries to use PulseAudio to send audio over A2DP to another device with bluez-alsa, that doesn't work because PulseAudio uses an incorrect RTP payload type and bluez-alsa checks that the RTP payload type is correct. According to the A2DP spec, the payload type should be set to a number between 96 and 127.
Fixes: #591 (closed)