helm: fix the invalid nodeAffinity configuration in the comment

This commit fixes the missing indentation for nodeAffinity configuration
example in the comment. If users try to use the example configuration by
copy and paste, an error will occur.

Signed-off-by: Kazuki Suda <kazuki.suda@gmail.com>

deploy/charts/rook-ceph-cluster/values.yaml

@@ -188,8 +188,8 @@ cephClusterSpec:
   #           - matchExpressions:
   #             - key: role
   #               operator: In
-  #             values:
-  #             - storage-node
+  #               values:
+  #               - storage-node
   #     podAffinity:
   #     podAntiAffinity:
   #     topologySpreadConstraints: