perf tools: Add the legacy-cache.json to .gitignore

The commit 0012e0f ("perf jevents: Add legacy-hardware and
legacy-cache json") will auto-generate: "pmu-events/arch/common/common/legacy-cache.json".

Reviewed-by: James Clark <[email protected]>
Signed-off-by: Haiyue Wang <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: haiyuewa

tools/perf/.gitignore

@@ -36,6 +36,7 @@ config.mak.autogen
 util/intel-pt-decoder/inat-tables.c
 arch/*/include/generated/
 trace/beauty/generated/
+pmu-events/arch/common/common/legacy-cache.json
 pmu-events/pmu-events.c
 pmu-events/jevents
 pmu-events/metric_test.log