perf pmu: Support more complex PMU event aliasing

The jevent "Unit" field is used for uncore PMU alias definition.

The form uncore_pmu_example_X is supported, where "X" is a wildcard, to
support multiple instances of the same PMU in a system.

Unfortunately this format not suitable for all uncore PMUs; take the
Hisi DDRC uncore PMU for example, where the name is in the form
hisi_scclX_ddrcY.

For for current jevent parsing, we would be required to hardcode an
uncore alias translation for each possible value of X. This is not
scalable.

Instead, add support for "Unit" field in the form "hisi_sccl,ddrc",
where we can match by hisi_scclX and ddrcY. Tokens  in Unit field are
delimited by ','.

Signed-off-by: John Garry <john.garry@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxarm@huawei.com
Link: http://lkml.kernel.org/r/1561732552-143038-2-git-send-email-john.garry@huawei.com


[ Shut up older gcc complianing about the last arg to strtok_r() being uninitialized, set that tmp to NULL ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>