vulkan: Support asymmetric FA in coopmat2 path

[jeffbolznv]

Overview

There has been some recent interest/experimentation with mixed quantization types for FA. I had originally designed the cm2 FA shader with this in mind (because I didn't realize it wasn't supported at the time!), this change adds the missing pieces and enables it.

Also support Q1_0 since people have been trying that out (seems crazy, but who knows).

We should be able to do similar things in the coopmat1/scalar path, but there's another change open against the scalar path and I don't want to conflict.

Requirements

• I have read and agree with the contributing guidelines
• AI usage disclosure: YES, I used Cursor (composer-2-fast) for most of this change.

[Green-Sky]

I have not run it, but at first glance the code looks like iq4_nl is missing.

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Thanks for providing this, I will see what testing I can get out of this. But from the testing I did with q1_0 with nkvo, q1_0 hurts the performance of the model too much. It is more or less equivalent to a thirding or quatering of model parameter count.

[jeffbolznv]

I took out iq4nl because I wanted to avoid allocating and initializing the shared memory table if it's not used. Is this something people actually use? If so, I can put it back.