[WIP] kernel/zarch: Fix cscal and zscal #5690

Job	Run time
msys2 (UCRT64, int64, Release)	12m 52s
build (ubuntu-latest, gfortran, make)	21m 19s
build (macos-latest, gfortran, make)	11m 6s
msys2 (MINGW32, int32, Release)	14m 20s
build (ubuntu-latest, flang, cmake)	26m 0s
build (ubuntu-latest, flang, make)	6m 44s
msys2 (CLANG64, int64, Release)	17m 27s
build (ubuntu-latest, gfortran, cmake)	6m 42s
msys2 (UCRT64, int32, Release)	12m 52s
msys2 (CLANG64, int32, Release)	14m 46s
build (macos-latest, gfortran, cmake)	15m 9s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	11m 52s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	2m 42s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 34s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 27s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 45s
neoverse_build	4m 34s
	3h 8m 11s

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