apr: fix race condition in apr reset

Since apr reset is scheduled in a workqueue, it is possible that before
completion of previous session apr_deregister(), new session of apr_register()
can happen in ssr scenario. Some of the variables are not reset properly
due to this race condition. Fix this issue by failing apr_register() till
apr_deregister() is completed.

Change-Id: I203e356e8330d8633d78bbfc6ae0165afa79f1f3
Signed-off-by: Vidyakumar Athota <[email protected]>

ipc/apr.c

@@ -543,6 +543,7 @@ struct apr_svc *apr_register(char *dest, char *svc_name, apr_fn svc_fn,
 	if (svc->need_reset) {
 		mutex_unlock(&svc->m_lock);
 		pr_err("APR: Service needs reset\n");
+		svc = NULL;
 		goto done;
 	}
 	svc->id = svc_id;