perf pmu: Fix perf stat output with correct scale and unit

The perf_pmu__parse_* functions for the sysfs files of pmu event’s
scale, unit, per-pkg and snapshot were updated in commit 7b723dbb
("perf pmu: Be lazy about loading event info files from sysfs").
However, the paths for these sysfs files were incorrect. This resulted
in perf stat reporting values with wrong scaling and missing units. This
is fixed by correcting the paths for these sysfs files.

Before this fix:

 $sudo perf stat -e power/energy-pkg/ -- sleep 2

 Performance counter stats for 'system wide':

   351,217,188,864      power/energy-pkg/

          2.004127961 seconds time elapsed

After this fix:

 $sudo perf stat -e power/energy-pkg/ -- sleep 2

 Performance counter stats for 'system wide':

             80.58 Joules power/energy-pkg/

 	     2.004009749 seconds time elapsed

Fixes: 7b723dbb ("perf pmu: Be lazy about loading event info files from sysfs")
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: ravi.bangoria@amd.com
Cc: sandipan.das@amd.com
Cc: james.clark@arm.com
Cc: kan.liang@linux.intel.com
Link: https://lore.kernel.org/r/20230920122349.418673-1-wyes.karny@amd.com


Signed-off-by: Namhyung Kim <namhyung@kernel.org>