The Retire Latency field is added in the var3_w of the
PERF_SAMPLE_WEIGHT_STRUCT. The Retire Latency reports pipeline stall of
this instruction compared to the previous instruction in cycles.  That's
quite useful to display the information with perf mem report.

The p_stage_cyc for Power is also from the var3_w. Union the p_stage_cyc
and retire_lat to share the code.

Implement X86 specific codes to display the X86 specific header.

Add a new sort key retire_lat for the Retire Latency.
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20230104201349.1451191-8-kan.liang@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>