Revert "sched/psi: Allow unprivileged polling of N*2s period"

This reverts commit d5dca197 which is
commit d82caa27 upstream.

It is part of a patch series that breaks the Android API.  If this
series is needed in Android devices in the future, it can come back in
an ABI-safe manner.

Bug: 161946584
Change-Id: Ibe2e8b99fff1782f9bfc2d633ac748741f119256
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>