coresight: configfs: Allow configfs to activate configuration

Adds configfs attributes to allow a configuration to be enabled for use
when sysfs is used to control CoreSight.

perf retains independent enabling of configurations.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20211124200038.28662-6-mike.leach@linaro.org


Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>