Explicit unaligned vector load/stores in PPC64LE GEMV kernels #5583

Job	Run time
neoverse_build	8m 13s
msys2 (UCRT64, int64, Release)	12m 48s
msys2 (UCRT64, int32, Release)	12m 9s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	13m 4s
msys2 (CLANG64, int32, Release)	1h 8m 53s
build (ubuntu-latest, gfortran, cmake)	46m 17s
msys2 (CLANG64, int64, Release)	1h 12m 1s
build (ubuntu-latest, flang, make)	4m 41s
build (ubuntu-latest, flang, cmake)	10m 12s
msys2 (MINGW32, int32, Release)	17m 5s
build (macos-latest, gfortran, make)	10m 20s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 31s
build (macos-latest, gfortran, cmake)	26m 54s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	2m 30s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 53s
build (ubuntu-latest, gfortran, make)	22m 15s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	4m 2s
	5h 37m 48s

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