Summary

Make the following changes to the IBM Music Feature Card:

• Run the interrupt handler routine timer with a longer interval
• Significant improvements to the timers: this fixes the elapsed time counting up too quickly in PLAYREC and the 8911 Timer Error in IBM Advanced Diagnostics

Checklist

• Closes #xxx
• I have tested my changes locally and validated that the functionality works as intended
• I have discussed this with core contributors already
• This pull request requires changes to the ROM set
  • I have opened a roms pull request - https://github.com/86Box/roms/pull/changeme/
• This pull request requires changes to the asset set
  • I have opened an assets pull request - https://github.com/86Box/assets/pull/changeme/

References

Provide links to datasheets or other documentation that helped you implement this pull request.