ANDROID: sched: Remove sysctl_sched_is_big_little

With the new wakeup approach this sysctl is not necessary any more.

Change-Id: I52114b3c918791f6a4f9f30f50002919ccbc1a9c
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
(cherry picked from commit 885c0d503bcdf0ef4e9b46822496f16b20aa3bbd)
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>