Aztech AZT1605 (Clinton/Nova 16 Extra) fixes

[win2kgamer]

Summary

Resolves several issues with the Sound Galaxy Clinton/Nova 16 Extra card (AZT1605):

• Aztech variable command length handling now works properly resolving the hang when writing the EEPROM in MIXTSR
• SB DSP RP is incremented when Aztech command 0x08 subcommand 0x01 is run by EMUTSR which resolves HWSET failing to detect the card if run after EMUTSR
• AZT1605 SBPro mixer readout ports (in the 628-62Fh/648-64Fh range) are implemented resolving the scrambled mixer values in MIXTSR and HWSET
• AZT1605 now restores the WSS mixer values from the EEPROM and sane default values are used resolving the reported issue of the OPL3 being silent after boot
• AZT1605 always uses the WSS AUX1 mixer allowing the CD volume slider to work
• AZT1605 now filters the OPL3 through the WSS AUX2 mixer allowing the FM volume slider to work

Also added some basic logging to the Aztech code.

Checklist

• Closes Various issues with the AZTech Sound Galaxy Clinton (Nova 16 Extra) in MS-DOS #5113
• 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/

References

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