Update aws-k8s-cni.yaml

[cheng0214]

Issue #, if available:
when i try to create kops cluster with vpc-cni network plugin, the master node has these taints, so
pod is not scheduled to master node.

Description of changes:
Add toleration to daemonset can fix this.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[mogren]

@cheng0214 By default, the CNI will tolerate any taint, see the official documentation:

An empty key with operator Exists matches all keys, values and effects which means this will tolerate everything.

That means the aws-node daemonset should schedule a pod on all nodes by default. For a related issue, see #508

[cheng0214]

ok, I will close the PR. thanks you