sched/deadline: Split cpudl_set() into cpudl_set() and cpudl_clear()

sched/deadline: Split cpudl_set() into cpudl_set() and cpudl_clear()

These 2 exercise independent code paths and need different arguments.

After this change, you call:

  cpudl_clear(cp, cpu);
  cpudl_set(cp, cpu, dl);

instead of:

  cpudl_set(cp, cpu, 0 /* dl */, 0 /* is_valid */);
  cpudl_set(cp, cpu, dl, 1 /* is_valid */);

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-dl@retis.sssup.it
Link: http://lkml.kernel.org/r/1471184828-12644-4-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>