cgroup: net_prio: Mark local used function static

net_prio_attach() is only access via cgroup_subsys callbacks,
therefore we can reduce the visibility of this function.
Signed-off-by: NDaniel Wagner <daniel.wagner@bmw-carit.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <netdev@vger.kernel.org>
Cc: <cgroups@vger.kernel.org>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/netprio_cgroup.c

@@ -248,7 +248,7 @@ static int update_netprio(const void *v, struct file *file, unsigned n)
 	return 0;
 }
 
-void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
+static void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
 {
 	struct task_struct *p;
 	void *v;