Requires corresponding updates to TurboGrafx16_MiSTer.
Currently works when audio is running; pause/stop will need further updates.
Currently only supports a single, *.sub file which represents the whole disc.
Adjustment to head seek timing:
When seeking to audio tracks, there is a delay of between 130ms and 290ms between the status confirmation of completion and the start of audio. 80% of the time this is 220ms +/-20ms and does not appear to be related to either seek distance or location on disc.
This fix inserts a delay between head seek arrival status confirmation and the start of audio play, without changing the total delay (ie. status is retruned earlier where appropriate).
This fixes Last Alert's excess sound, but may also fix other games' sound.
This was tested against main games which have presented issues with seektime in the past.
* pcecd: read 256 sectors when length is 0 (Kabuki Itouryodan).
* pcecd: send status immediately for commands with instant execution (Bomberman: Panic Bomber), some cleanup
