Fix errors reported by cppcheck in src/quad/sleefsimdqp.c #274

Job	Run time
build-native-ubuntu-latest-gcc	3m 9s
build-native-ubuntu-latest-llvm	3m 49s
build-native-ah-ubuntu_22_04-c7g_2x-50-gcc	2m 7s
build-native-ah-ubuntu_22_04-c7g_2x-50-llvm	2m 14s
test-native-ubuntu-latest-gcc	9m 14s
build-armhf-gcc	1m 59s
test-native-ubuntu-latest-llvm	7m 54s
build-armhf-llvm	1m 39s
test-native-ah-ubuntu_22_04-c7g_2x-50-gcc	2m 41s
build-ppc64el-gcc	2m 26s
test-native-ah-ubuntu_22_04-c7g_2x-50-llvm	2m 32s
build-ppc64el-llvm	3m 10s
build-s390x-gcc	2m 6s
build-s390x-llvm	1m 59s
build-riscv64-llvm	2m 39s
test-armhf-gcc (qemu_cpu: "max")	14m 27s
test-armhf-llvm (qemu_cpu: "max")	13m 25s
test-ppc64el-gcc (qemu_cpu: "power10")	26m 25s
test-ppc64el-llvm (qemu_cpu: "power10")	24m 16s
test-s390x-gcc (qemu_cpu: "")	21m 27s
test-s390x-llvm (qemu_cpu: "")	18m 34s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=false")	12m 45s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=128,elen=64,vext_spec=v1.0")	30m 7s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=256,elen=64,vext_spec=v1.0")	39m 59s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=512,elen=64,vext_spec=v1.0")	59m 12s
	5h 10m 15s

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