prov/util: Fix revert PR #9377

I mistakenly reverted ep->lock to always be an ofi_mutex.
Restore ep->lock to depend on domain threading model

Signed-off-by: Seth Zegelstein <szegel@amazon.com>

prov/util/src/util_ep.c

@@ -247,8 +247,9 @@ int ofi_endpoint_init(struct fid_domain *domain, const struct util_prov *util_pr
 	if (util_domain->eq)
 		ofi_ep_bind_eq(ep, util_domain->eq);
 
-	/* TODO Figure out how to optimize this lock for rdm and msg endpoints */
-	ret = ofi_genlock_init(&ep->lock, OFI_LOCK_MUTEX);
+	ret = ofi_genlock_init(&ep->lock,
+			       ep->domain->threading != FI_THREAD_SAFE ?
+			       OFI_LOCK_NOOP : OFI_LOCK_MUTEX);
 	if (ret)
 		return ret;