UPSTREAM: sched/core: Add missing update_rq_clock() call in set_user_nice()

UPSTREAM: sched/core: Add missing update_rq_clock() call in set_user_nice()

Address this rq-clock update bug:

  WARNING: CPU: 30 PID: 195 at ../kernel/sched/sched.h:797 set_next_entity()
  rq->clock_update_flags < RQCF_ACT_SKIP

  Call Trace:
    dump_stack()
    __warn()
    warn_slowpath_fmt()
    set_next_entity()
    ? _raw_spin_lock()
    set_curr_task_fair()
    set_user_nice.part.85()
    set_user_nice()
    create_worker()
    worker_thread()
    kthread()
    ret_from_fork()

Change-Id: I8fb2653b2d9cb3bbc1637c1bcbf1c0645752ef12
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit 2fb8d36787affe26f3536c3d8ec094995a48037d)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>