ANDROID: sched: Make the cpu_util* accessors available without sugov

In preparation for the introduction of the boost hold feature in
SchedTune, make the cpu_util_* signals available even without sugov,
hence making the stune integration a lot easier without breaking other
platforms

Change-Id: I77c14b6fd470a41ffb3ac510b76395ebc116ddfd
Signed-off-by: Quentin Perret <quentin.perret@arm.com>