cpuset: drop spurious retval assignment in proc_cpuset_show()

proc_cpuset_show() has a spurious -EINVAL assignment which does
nothing.  Remove it.

This patch doesn't make any functional difference.

tj: Rewrote patch description.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cpuset.c

@@ -2677,7 +2677,6 @@ static int proc_cpuset_show(struct seq_file *m, void *unused_v)
 	if (!tsk)
 		goto out_free;
 
-	retval = -EINVAL;
 	rcu_read_lock();
 	css = task_subsys_state(tsk, cpuset_subsys_id);
 	retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);