core: fix openshift security context

The MKNOD capability was missing and due to recent addition some pod now
only require this cap as well as privileged.
The cap must be explicitly exposed so it can be requested by a pod.

Closes: #9234
Signed-off-by: Sébastien Han <seb@redhat.com>
(cherry picked from commit b38f430)

cluster/examples/kubernetes/ceph/operator-openshift.yaml

@@ -14,9 +14,9 @@ allowPrivilegedContainer: true
 allowHostNetwork: true
 allowHostDirVolumePlugin: true
 priority:
-allowedCapabilities: []
 allowHostPorts: true
 allowHostPID: true # remove this once we drop support for Nautilus
+allowedCapabilities: ["MKNOD"]
 allowHostIPC: true
 readOnlyRootFilesystem: false
 requiredDropCapabilities: []