perf vendor events arm64: Add branch metrics for neoverse-n2-v2

Add branch related metrics.

Reviewed-by: John Garry <[e-mail]>
Signed-off-by: Jing Zhang <[e-mail]>
Acked-by: Ian Rogers <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andrew Kilroy <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Mike Leach <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Shuai Xue <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Xing Zhengjun <[e-mail]>
Cc: Zhuo Song <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json

···
         "MetricGroup": "Cache",
         "MetricName": "ll_cache_read_hit_rate",
         "ScaleUnit": "100%"
+    },
+    {
+        "MetricExpr": "BR_MIS_PRED_RETIRED / INST_RETIRED * 1000",
+        "BriefDescription": "The rate of branches mis-predicted per kilo instructions",
+        "MetricGroup": "Branch",
+        "MetricName": "branch_mpki",
+        "ScaleUnit": "1MPKI"
+    },
+    {
+        "MetricExpr": "BR_RETIRED / INST_RETIRED * 1000",
+        "BriefDescription": "The rate of branches retired per kilo instructions",
+        "MetricGroup": "Branch",
+        "MetricName": "branch_pki",
+        "ScaleUnit": "1PKI"
+    },
+    {
+        "MetricExpr": "BR_MIS_PRED_RETIRED / BR_RETIRED",
+        "BriefDescription": "The rate of branches mis-predited to the overall branches",
+        "MetricGroup": "Branch",
+        "MetricName": "branch_miss_pred_rate",
+        "ScaleUnit": "100%"
     }
 ]