FAQ.md: fix kubeadm init instructions
FAQ.md: fix kubeadm init instructions

The current version of FAQ.md contains an incorrect example of how to instruct kubelet to prefer containerd over docker. More specifically, it refers to a non-existent `--cni-socket` flag whereas it should have been `--cri-socket`.

The suggested PR fixes that.
google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor