To prevent rendering samples for systems that are not in use.
Additionally, it gives the systems more flexibility to render the samples
according to their specific configuration.
as of now the SSG part of these chips is handled by a DivPlatformAY8910
within the DivPlatformYM2610.
this means less code duplication and therefore prepares for
OPN/OPNA support.
Allow 8 bit volume for YM2610 ADPCM-B
Remove sample mode macro in YM2610, it's always enabled and seperated channels.
TODO: ADPCM-B is still not implemented, FM Channel 2 is silenced in extended channel 3 configuration