sched: Preserve the nice level over sched_setscheduler() and sched_setparam() calls

sched: Preserve the nice level over sched_setscheduler() and sched_setparam() calls

Previously sched_setscheduler() and sched_setparam() would not affect
the nice value of a task, restore this behaviour.

Signed-off-by: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Michael wang <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Fixes: d50dde5a10f3 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>