sched: Remove rq->cpu_capacity_orig and capacity_orig_of()

Currently there are two different ways to get the original (maximum)
capacity of a CPU within the task scheduler and in other subsystems
(Energy Model, Cpufreq cooling).

(a) Get rq->cpu_capacity_orig via capacity_orig_of().

(b) Get SCHED_CAPACITY_SCALE via the default arch_scale_cpu_capacity()
    for SMP or the per-cpu cpu_scale via topology_update_cpu_topology()
    which defines arch_scale_cpu_capacity() on arm/arm64 systems
    arm/arm64 systems.

Cleanup by using only 1 way. Remove (a) and transfer all users to (b).

Reasons for doing this and not vice versa are:

(1) The default SMP implementation of arch_scale_cpu_capacity()
    [include/linux/sched/topology.h] is a compile-time constant.

(2) capacity_orig_of() is only defined for CONFIG_SMP. The task
    scheduler needs it for !CONFIG_SMP as well in update_curr_dl().

(3) capacity_orig_of() is only defined for the task scheduler
    [kernel/sched/sched.h]. It shouldn't be exported wider since struct
    rq internals, like cpu_capacity_orig, shouldn't be exposed.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>