cgroup/cpuset: remove unneeded header files

Remove some unnecessary header files. No functional change intended.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup/cpuset.c

@@ -37,12 +37,10 @@
 #include <linux/sched/deadline.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>
-#include <linux/seq_file.h>
 #include <linux/security.h>
 #include <linux/spinlock.h>
 #include <linux/oom.h>
 #include <linux/sched/isolation.h>
-#include <linux/mutex.h>
 #include <linux/cgroup.h>
 #include <linux/wait.h>