ipc4: mixin: Fix HiFi3 impl of 24-bit mixing #19719

Job	Run time
manifest-check	44s
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	6m 26s
LP64-WIP	4m 1s
build-linux (mnfst, mtl)	4m 42s
build-windows (imx8 imx8x imx8m imx8ulp)	8m 13s
build-linux (mnfst, lnl)	4m 31s
build-windows (mtl)	7m 19s
build-linux (mnfst, ptl)	4m 24s
build-windows (tgl tgl-h)	6m 49s
build-linux (mnfst, tgl tgl-h)	5m 29s
build-windows (-d, mtl)	6m 3s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	7m 13s
build-linux (zmain, mtl)	4m 29s
build-linux (zmain, lnl)	4m 33s
build-linux (zmain, ptl)	4m 34s
build-linux (zmain, tgl tgl-h)	6m 25s
build-linux (-d, mnfst, mtl)	5m 8s
build-linux (mnfst, --all)	15m 3s
compare-linux-win	26s
	1h 46m 32s

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