kernel/riscv64:Added support for omatcopy on RISCV64_ZVL256B #5653

Job	Run time
neoverse_build	8m 15s
msys2 (UCRT64, int32, Release)	13m 16s
msys2 (UCRT64, int64, Release)	14m 56s
msys2 (MINGW32, int32, Release)	17m 14s
msys2 (CLANG64, int32, Release)	1h 10m 11s
build (macos-latest, gfortran, make)	3m 33s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	11m 54s
msys2 (CLANG64, int64, Release)	15m 56s
build (ubuntu-latest, flang, make)	5m 57s
build (ubuntu-latest, flang, cmake)	10m 32s
build (ubuntu-latest, gfortran, make)	22m 6s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 31s
build (ubuntu-latest, gfortran, cmake)	44m 59s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 46s
build (macos-latest, gfortran, cmake)	12m 55s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 55s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	3m 3s
	4h 24m 59s

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