Summary

1. Apparently some stuff uses read-only port 0x86ee and expects it to return 0 while port 0xf6ee is an alias to 0x82e8, this should fix hangs in Majong 8514 using ATI's DOS drivers.
2. 8514 data available bits are reset properly when new parameters for a new command are installed (port 0xCEEE), fixes remaining hangs with some stuff.

Checklist

• Closes Emulation of IBM 8514/A does not works with DOS applicatios even with the HDPCDOS driver loaded #3952
• 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/

References

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