buildroot

mpd: bump to version 0.16.2 and bugfix

Bump mpd server to version 0.6.12
Also make ffmpeg support conditional on IPv6 since the new ffmpeg
version requires it.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>