bindings: pmic-glink: add protection domain restart (PDR) support

Add "qcom,protection-domain" for PMIC Glink device so that it can
register for PDR notifications from a service available under the
specified path in a remote subsystem. Upon a state transition, it
can be delivered to its clients if they've registered for it.

Change-Id: I1ceb0b9400c83e9132ea22ca9fbb4ad3b6c3b33c