perf vendor events arm64: Add JSON metrics for Yitian 710 DDR

Add JSON metrics for T-HEAD Yitian 710 SoC DDR.
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Shuai Xue <xueshuai@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zhuo Song <zhuo.song@linux.alibaba.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/1690528175-2499-3-git-send-email-renyu.zj@linux.alibaba.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/arch/arm64/freescale/yitian710/sys/metrics.json

+[
+	{
+		"MetricName": "ddr_read_bandwidth.all",
+		"BriefDescription": "The ddr read bandwidth(MB/s).",
+		"MetricGroup": "ali_drw",
+		"MetricExpr": "hif_rd * 64 / 1e6 / duration_time",
+		"ScaleUnit": "1MB/s",
+		"Unit": "ali_drw",
+		"Compat": "ali_drw_pmu"
+	},
+	{
+		"MetricName": "ddr_write_bandwidth.all",
+		"BriefDescription": "The ddr write bandwidth(MB/s).",
+		"MetricGroup": "ali_drw",
+		"MetricExpr": "(hif_wr + hif_rmw) * 64 / 1e6 / duration_time",
+		"ScaleUnit": "1MB/s",
+		"Unit": "ali_drw",
+		"Compat": "ali_drw_pmu"
+	}
+]