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

This reverts commit b2f7d750 which is
commit e23edc86 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I15323a8e18cf1f7c4051f5aa3e9f1540f6b15100
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>