perf cs-etm: Fix the assert() to handle captured and unprocessed cpu trace

perf cs-etm: Fix the assert() to handle captured and unprocessed cpu trace

If one builds perf with DEBUG=1, captures data on multiple CPUs and
finally runs 'perf report -C <cpu>' for only one of the cpus, assert()
aborts the program. This happens because there are empty queues with
format set.

This patch changes the condition to abort only if a queue is not empty
and if the format is unset.

  $ make -C tools/perf DEBUG=1 CORESIGHT=1 CSLIBS=/usr/lib CSINCLUDES=/usr/include install
  $ perf record -o kcore --kcore -e cs_etm/timestamp/k -s -C 0-1 dd if=/dev/zero of=/dev/null bs=1M count=1
  $ perf report --input kcore/data --vmlinux=/home/ikoskine/projects/linux/vmlinux -C 1
  Aborted (core dumped)

Fixes: 57880a7966be510c ("perf: cs-etm: Allocate queues for all CPUs")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240924233930.5193-1-ilkka@os.amperecomputing.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>