selftests/bpf: Fix vmtest.sh to launch smp vm.

Fix typo in vmtest.sh to make sure it launch proper vm with 8 cpus. Signed-off-by: Yucong Sun <fallentree@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220217155212.2309672-1-fallentree@fb.com

Author: Yucong Sun

tools/testing/selftests/bpf/vmtest.sh

@@ -241,7 +241,7 @@ EOF
 -nodefaults \
 -display none \
 -serial mon:stdio \
-"${qemu_flags[@]}" \
+"${QEMU_FLAGS[@]}" \
 -enable-kvm \
 -m 4G \
 -drive file="${rootfs_img}",format=raw,index=1,media=disk,if=virtio,cache=none \