Revert "sched: Unify more update_curr*()"

This reverts commit 24617f9c which is
commit c708a4dc 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: If9df53b06a34ac009feba517ca99a6893699dd38
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>