Documentation: coresight: Fix documentation issue

Documentation: coresight: Fix documentation issue

Fix the description of the directories and attributes used
in cs_etm as used by perf.

Drop the references to the 'configurations' sub-directory which
had been removed in an earlier version of the patchset.

Fixes: f71cd93d5ea4 ("Documentation: coresight: Add documentation for CoreSight config")
Reported-by: German Gomex <german.gomez@arm.com>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20211117164220.14883-1-mike.leach@linaro.org
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>