perf cs-etm: Move mapping of Trace ID and cpu into helper function

perf cs-etm: Move mapping of Trace ID and cpu into helper function

The information to associate Trace ID and CPU will be changing.

Drivers will start outputting this as a hardware ID packet in the data
file which if present will be used in preference to the AUXINFO values.

To prepare for this we provide a helper functions to do the individual ID
mapping, and one to extract the IDs from the completed metadata blocks.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Acked-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Darren Hart <darren@os.amperecomputing.com>
Cc: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230331055645.26918-2-mike.leach@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>