perf cs-etm: Only setup queues when they are modified

Continually creating queues in cs_etm__process_event() is unnecessary.
They only need to be created when a buffer for a new CPU or thread is
encountered. This can be in two places, when building the queues in
advance in cs_etm__process_auxtrace_info(), or in
cs_etm__process_auxtrace_event() when data_queued is false and the
index wasn't available (pipe mode).

This change will allow the 'formatted' decoder setting to applied when
iterating over aux records in a later commit.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>