sched/fair: Rename check_preempt_curr() to wakeup_preempt()

[ Upstream commit e23edc86 ]

The name is a bit opaque - make it clear that this is about wakeup
preemption.

Also rename the ->check_preempt_curr() methods similarly.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Stable-dep-of: 0664e2c3 ("sched/deadline: Fix warning in migrate_enable for boosted tasks")
Signed-off-by: Sasha Levin <sashal@kernel.org>