Add support for Channel 11 as a rhythm channel

[s11141827]

No description provided.

[wyskoj]

Per the GM 2 spec:

Channels 10 and 11 are special in that they can function as a Melody Channel or a Rhythm Channel, depending upon the
Bank Select message. On Channels 10 and 11, Bank Select 78H/xxH followed by a Program Change will cause the
Channel to become a Rhythm Channel, using the Drum Set selected by the Program Change. Bank Select 79H/xxH
followed by a Program Change will cause the Channel to become a Melody Channel, with the sound or timbre selected
by the Program Change.

[Sonic-TV]

You could add XG rhythm channel support as well. (as it just uses MSB#127 for rhythm channels rather than SysExData / forced 10/11)

[s11141827]

OK that rocks.