connector/cn_proc: Use task_is_in_init_pid_ns()

This patch replaces open code with task_is_in_init_pid_ns() to check if
a task is in root PID namespace.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/connector/cn_proc.c

@@ -358,7 +358,7 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
 	 * other namespaces.
 	 */
 	if ((current_user_ns() != &init_user_ns) ||
-	    (task_active_pid_ns(current) != &init_pid_ns))
+	    !task_is_in_init_pid_ns(current))
 		return;
 
 	/* Can only change if privileged. */