speaker amp control (faux123) - squashed two commits

speaker amp control: initial release for speaker amp control
https://github.com/faux123/mako/commit/475e985e1f48484355d66ccf93f50b28afb9d21b

speaker amp control: allowed all configurable registers to be adjusted
https://github.com/faux123/mako/commit/efce8f98ce5198b324f6f83677c1d471edc35c13