UPSTREAM: sched/topology: Add static_key for asymmetric CPU capacity optimizations

The existing asymmetric CPU capacity code should cause minimal overhead
for others. Putting it behind a static_key, it has been done for SMT
optimizations, would make it easier to extend and improve without
causing harm to others moving forward.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-2-git-send-email-morten.rasmussen@arm.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit df054e8445a4011e3d693c2268129c0456108663)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>

Change-Id: I6f8de25a9bb593a0032ad0ad7977c269b180ec51