perf auxtrace: Remove unused 'pmu' pointer from struct auxtrace_record

perf auxtrace: Remove unused 'pmu' pointer from struct auxtrace_record

The 'pmu' pointer in the auxtrace_record structure is not used after
support multiple AUX events, remove it.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20240806204130.720977-3-leo.yan@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>