bmxtranswrap: set read limits when output duration is 0
bmxtranswrap: set read limits when output duration is 0

Set the read limits when duration is 0 so that
reader->GetReadDuration() can be used in that case and it would
return 0.

stuarthicks/bmx,stuarthicks/bmx,kierank/bmxlib-bmx,ebu/ebu-bmx,Limecraft/ebu-bmx,kierank/bmxlib-bmx,ebu/ebu-bmx,xunchangguo/BMX,kierank/bmxlib-bmx,stuarthicks/bmx,xunchangguo/BMX,Limecraft/ebu-bmx,Limecraft/ebu-bmx,xunchangguo/BMX,ebu/ebu-bmx