perf script: Print PERF_AUX_FLAG_COLLISION flag

Print out the collision flag for AUX trace data. This is helpful for
inspecting sample collisions.

After:

  0x217b60@/data_nvme1n1/niayan01/upstream/perf.data [0x40]: event: 11
  .
  . ... raw event: size 64 bytes
  .  0000:  0b 00 00 00 00 00 40 00 d2 ef 3f 00 00 00 00 00  ......@...?.....
  .  0010:  ff 0f 00 00 00 00 00 00 08 00 00 00 00 00 00 00  ................
  .  0020:  1c 01 00 00 1c 01 00 00 10 bf 38 d6 11 01 00 00  ..........8.....
  .  0030:  03 00 00 00 00 00 00 00 06 00 00 00 00 00 00 00  ................

  3 1176120114960 0x217b60 [0x40]: PERF_RECORD_AUX offset: 0x3fefd2 size: 0xfff flags: 0x8 [C]

The added character '[C]' indicates the collision.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20250528153519.188644-1-leo.yan@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: Leo-Yan

tools/perf/util/event.c

@@ -449,12 +449,13 @@ int perf_event__exit_del_thread(const struct perf_tool *tool __maybe_unused,
 
 size_t perf_event__fprintf_aux(union perf_event *event, FILE *fp)
 {
-	return fprintf(fp, " offset: %#"PRI_lx64" size: %#"PRI_lx64" flags: %#"PRI_lx64" [%s%s%s]\n",
+	return fprintf(fp, " offset: %#"PRI_lx64" size: %#"PRI_lx64" flags: %#"PRI_lx64" [%s%s%s%s]\n",
 		       event->aux.aux_offset, event->aux.aux_size,
 		       event->aux.flags,
 		       event->aux.flags & PERF_AUX_FLAG_TRUNCATED ? "T" : "",
 		       event->aux.flags & PERF_AUX_FLAG_OVERWRITE ? "O" : "",
-		       event->aux.flags & PERF_AUX_FLAG_PARTIAL   ? "P" : "");
+		       event->aux.flags & PERF_AUX_FLAG_PARTIAL   ? "P" : "",
+		       event->aux.flags & PERF_AUX_FLAG_COLLISION ? "C" : "");
 }
 
 size_t perf_event__fprintf_itrace_start(union perf_event *event, FILE *fp)