Support Yamaha MA series sound chip

[ADG664]

MA- Series is a FM+PCM composite chip designed by Yamaha Company for the previous flip-slide mobile phones/portable devices/used for playing Midi ringtones on mobile devices! The known chip models are: MA-2/YMU759B, MA-3/YMU762C, MA-5/YMU765Q and MA-7/YMU786W MA series, which are the most successful and complete FM synthetic chips ever produced by Yamaha Company! If we can successfully join him in furnace? Then he is one of the greatest projects in the world!

[tildearrow]

MA-2 is already half-supported and can be enabled through the use of a cheat code (or by loading a DefleMask 10 or earlier .dmf).

[freq-mod]

Mobile Yamaha FM chips are horrendously underdocumented. No real, proper emulation core for it exists, except Yamaha's proprietary one, which is closed source and most likely inaccurate. A new one would have to be made, requiring a lot of reverse-engineering effort. That being said, support for any MA chip is unlikely, they might be emulated by OPL3 (like MA-2 is currently done) or OPL4 (WIP as of now)