Math: Optimise 16-bit matrix multiplication functions. #385

Job	Run time
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	2m 31s
build-windows (imx8 imx8x imx8m imx8ulp)	2m 18s
build-linux (mnfst, mtl)	2m 31s
build-linux (mnfst, lnl)	2m 32s
build-windows (mtl)	2m 19s
build-linux (mnfst, tgl tgl-h)	2m 33s
build-windows (tgl tgl-h)	2m 20s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	2m 31s
build-linux (zmain, mtl)	2m 30s
build-windows (-d, mtl)	2m 17s
build-linux (zmain, lnl)	2m 31s
build-linux (zmain, tgl tgl-h)	2m 30s
build-linux (-d, mnfst, mtl)	2m 32s
LP64-WIP	2m 31s
manifest-check	40s
compare-linux-win	14s
	35m 20s

Provide feedback