perf stat: Fix metric-only aggregation index

Aggregation index was being computed using the evsel's cpumap which
may have a different (typically the same or fewer) entries.

Before:
```
$ perf stat --metric-only -A -M memory_bandwidth_total -a sleep 1

 Performance counter stats for 'system wide':

       MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total
CPU0                            12.8                           0.0                          12.9                          12.7                           0.0                          12.6
CPU1

       1.007806367 seconds time elapsed
```

After:
```
$ perf stat --metric-only -A -M memory_bandwidth_total -a sleep 1

 Performance counter stats for 'system wide':

       MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total MB/s  memory_bandwidth_total
CPU0                            15.4                           0.0                          15.3                          15.0                           0.0                          14.9
CPU18                            0.0                           0.0                          13.5                           5.2                           0.0                          11.9

       1.007858736 seconds time elapsed
```

Signed-off-by: Ian Rogers <[email protected]>                                  |
Acked-by: Namhyung Kim <[email protected]>
Cc: K Prateek Nayak <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Kaige Ye <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: John Garry <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions