adds wvSpltK optimization for skinny gemm.

[amd-hhashemi]

Adds wvSpltK optimization for skinny gemm; a less restrictive dot2-based solution.

FIX #xxxx (link existing issues this PR will resolve)

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[amd-hhashemi]

wvSpltK for skinny gemm

[gshtras]

Please don't enable these prints

[amd-hhashemi]

yup sorry

[gshtras]

Same here

[gshtras]

We are never going to reach here now, aren't we? Might as well remove the code path if we are certain that wvSpltK is always superior to LLMM1

[amd-hhashemi]

was missing k%8==0 condition. I left in LLMM1 because it was restrictive in passed, and we haven't extensively checked if there are cases where it outperforms.