sched/x86: Export 'percpu arch_freq_scale'

Commit:

  7bc26384

 ("sched/topology: Consolidate and clean up access to a CPU's max compute capacity")

removed rq->cpu_capacity_orig in favor of using arch_scale_freq_capacity()
calls. Export the underlying percpu symbol on x86 so that external trace
point helper modules can be made to work again.

Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240530181548.2039216-1-pauld@redhat.com