Fix MUX & DEMUX Configuration examples

[mwasko]

The example configuration matrix for MUX & DEMUX are invalid.

https://thesofproject.github.io/latest/algos/demux/demux.html

[juimonen]

@mwasko you mean because implementation has changed? I can also try to fix this if needed as I did the original...

[mwasko]

@juimonen the current MUX & DEMUX configuration matrix does not seem to make any sense, please take a look at it and let me know.

In MUX configuration example both Input Stream 1 and Stream 2 has channels 1,3,5,7 copied to all 8 output channels. It does not match the description.

[juimonen]

@mwasko oh I admit it is quite stupid example of a routing matrix... there's only 2 input/output channels (the red arrows), so essentially everything in the 8x8 matrix that falls out of the 2x2 upper left square is useless i.e. doesn't have any effect. Anyway I think nothing should stop you using this kind of matrix with 2 channel use case and actually you have to define 8x8 in topology even not using all 8 channels.

But yeah, maybe just zero out everything out of 2x2 would make it clear?

[lgirdwood]

@juimonen @bkokoszx lets roll all our demux/mux fixes up for v1.6. I think we are going in the right direction now.