ANDROID: arm: wire frequency-invariant accounting support up to the task scheduler

Commit dfbca41f ("sched: Optimize freq invariant accounting")
changed the wiring which now has to be done by associating
arch_scale_freq_capacity with the actual implementation provided
by the architecture.

Define arch_scale_freq_capacity to use the arch_topology "driver"
function topology_get_freq_scale() for the task scheduler's
frequency-invariant accounting instead of the default
arch_scale_freq_capacity() in kernel/sched/sched.h.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Change-Id: I04dc62ca703c8a1ebce52b35a39fdeaa55e44ca1
Signed-off-by: Chris Redpath <chris.redpath@arm.com>