Corrections and clean-up

Back to Q8_0 for attn_k and attn_v if 8 experts or more.

for attn_v and attn_k if experts>=4
GQA>=12 brought back to expert>=4 quant level instead of 8
GQA8 brought to GQA7, and GQA7 brought to GQA4.

Author: Nexesenex