perf stat: Fix cpu check to use id.cpu.cpu in aggr_printout()

perf stat: Fix cpu check to use id.cpu.cpu in aggr_printout()

'perf stat' has options to aggregate the counts in different modes like
per socket, per core etc. The function "aggr_printout" in
util/stat-display.c which is used to print the aggregates, has a check
for cpu in case of AGGR_NONE.

This check was originally using condition : "if (id.cpu.cpu > -1)". But
this got changed after commit df936cadfb58 ("perf stat: Add JSON output
option"), which added option to output json format for different
aggregation modes. After this commit, the check in "aggr_printout" is
using "if (id.core > -1)".

The old code was using "id.cpu.cpu > -1" while the new code is using
"id.core > -1". But since the value printed is id.cpu.cpu, fix this
check to use cpu and not core.

Suggested-by: Ian Rogers <irogers@google.com>
Suggested-by: James Clark <james.clark@arm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Ian Rogers <irogers@google.com>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20221006114225.66303-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>