perf jevents: Support unit value "cpu_core" and "cpu_atom"

perf jevents: Support unit value "cpu_core" and "cpu_atom"

For some Intel platforms, such as Alderlake, which is a hybrid platform
and it consists of atom cpu and core cpu. Each cpu has dedicated event
list. Part of events are available on core cpu, part of events are
available on atom cpu.

The kernel exports new cpu pmus: cpu_core and cpu_atom. The event in
json is added with a new field "Unit" to indicate which pmu the event
is available on.

For example, one event in cache.json,

    {
        "BriefDescription": "Counts the number of load ops retired that",
        "CollectPEBSRecord": "2",
        "Counter": "0,1,2,3",
        "EventCode": "0xd2",
        "EventName": "MEM_LOAD_UOPS_RETIRED_MISC.MMIO",
        "PEBScounters": "0,1,2,3",
        "SampleAfterValue": "1000003",
        "UMask": "0x80",
        "Unit": "cpu_atom"
    },

The unit "cpu_atom" indicates this event is only available on "cpu_atom".

In generated pmu-events.c, we can see:

{
        .name = "mem_load_uops_retired_misc.mmio",
        .event = "period=1000003,umask=0x80,event=0xd2",
        .desc = "Counts the number of load ops retired that. Unit: cpu_atom ",
        .topic = "cache",
        .pmu = "cpu_atom",
},

But if without this patch, the "uncore_" prefix is added before "cpu_atom",
such as:
        .pmu = "uncore_cpu_atom"

That would be a wrong pmu.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210427070139.25256-3-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>