* FA: provide work buffer for K repacking
* Add header to avoid comp0iler warnings
* WIP
* WIP
* WIP
* WIP
* Slightly better
* WIP (Zen4)
* WIP
* Try to improve for unusual number of heads/number of threads
* Use mul_mat_qX_0_q8_2_Tx for q6_0 in FA
* Use mul_mat_qX_0_q8_2_Tx for q4_0 in FA
* Use Sum4q4 for q4_0
* WIP
* WIP
* Much better FA TG with q8_0 KV cache
Just repack it even for TG. But do the repacking for k_step rows,
not the whole K tensor.
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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>
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