[PATCH] ASoC: max98357a: set channels_max to 4

[Pierre-Louis Bossart]

>> I don't think it's correct to declare 4-channel support at the
>> individual codec DAI level when in practice each device will be provided
>> with a TDM mask that selects two slots.
> 
> On this platform there is no TDM support, so there were two I2S data lines.
> 
>>
>> This is confusing device capabilities and TDM link configuration.
> 
> I see that in most of the use cases of multiple amps, we should use
> codecs and num_codecs of the link.
> But in this case we only want one codec to control the only GPIO
> shared by 4 max98357a amps
> I think we should be able to use 1 max98357 codec and 3 dummy codec to
> fulfill this use case.
> Not sure if the number of dummy codec would really matter.
> With num_codec > 1 we should be able to bypass the channel checking
> and just use the channel from CPU DAI.

Interesting, I haven't seen such 'multi-lane' solutions so far for I2S.