Revert "ANDROID: sched: Add vendor hooks for find_energy_efficient_cpu"

This reverts commit 147a9b3d as it
causes merge conflicts with 6.0-rc1.  If this is still needed, it can be
added back after 6.0-rc1 is merged.

Bug: 170507310
Cc: Rick Yiu <rickyiu@google.com>
Cc: Will McVicker <willmcvicker@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Icc8148871b5f2511c79ea5d7ff547b923acecf9a