BACKPORT: arm64: split counter validation function

In order for the counter validation function to be reused, split
validate_cpu_freq_invariance_counters() into:
 - freq_counters_valid(cpu) - check cpu for valid cycle counters
 - freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) -
   generic function that sets the normalization ratio used by
   topology_scale_freq_tick()

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201106125334.21570-3-ionela.voinescu@arm.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit bc3b6562)

Conflicts:
   arch/arm64/kernel/topology.c

BUG=b:249685960
TEST=Build

Change-Id: I0e29be320c78afe41d84b3b47353ab5a170d4a31
Signed-off-by: Masami Hiramatsu <mhiramat@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3939326


Reviewed-by: Suleiman Souhlal <suleiman@chromium.org>