perf probe: Rename err label

Rename err to out to avoid confusion because buf is still supposed to be
freed in non error cases.

Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Tested-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241211085525.519458-3-james.clark@linaro.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>