Bluetooth: AVRCP: Fix swappend SongPosition and SongLength

SongPosition and SongLength are swapped in Info column. Fix it.

Change-Id: I4c9bece51dbfe62885e8426a8aef07f336670099
Reviewed-on: https://code.wireshark.org/review/5287
Reviewed-by: Michal Labedzki <michal.labedzki@tieto.com>