Add KASSERT to ensure sane nsid.

All callers are currently filtering bad nsid to this function,
however, we'll have undefined behavior if that's not true. Add the
KASSERT to prevent that.

sys/dev/nvme/nvme.c

@@ -285,13 +285,18 @@ void
 nvme_notify_ns(struct nvme_controller *ctrlr, int nsid)
 {
 	struct nvme_consumer	*cons;
-	struct nvme_namespace	*ns = &ctrlr->ns[nsid - 1];
+	struct nvme_namespace	*ns;
 	void			*ctrlr_cookie;
 	uint32_t		i;
 
+	KASSERT(nsid <= NVME_MAX_NAMESPACES,
+	    ("%s: Namespace notification to nsid %d exceeds range\n",
+		device_get_nameunit(ctrlr->dev), nsid));
+
 	if (!ctrlr->is_initialized)
 		return;
 
+	ns = &ctrlr->ns[nsid - 1];
 	for (i = 0; i < NVME_MAX_CONSUMERS; i++) {
 		cons = &nvme_consumer[i];
 		if (cons->id != INVALID_CONSUMER_ID && cons->ns_fn != NULL &&