perf c2c: Organize metrics based on memory hierarchy

The metrics are not organized based on memory hierarchy, e.g. the tool
doesn't organize the metrics order based on memory nodes from the close
node (e.g. L1/L2 cache) to far node (e.g. L3 cache and DRAM).

To output metrics with more friendly form, this patch refines the
metrics order based on memory hierarchy:

  "Core Load Hit" => "LLC Load Hit" => "LLC Ld Miss" => "Load Dram"

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Joe Mario <jmario@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20201014050921.5591-4-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>