perf/x86/intel/uncore: Generalize get_topology() for SKX PMUs

Factor out a generic code from skx_iio_get_topology() to skx_pmu_get_topology()
to avoid code duplication. This code will be used by get_topology() procedure
for SKX UPI PMUs in the further patch.

Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20221117122833.3103580-6-alexander.antonov@linux.intel.com