coresight-etm4x: Controls pertaining to the reset, mode, pe and events

Adding sysfs entries to:
. set the tracing entity with default values.
. set various mode associated to the tracing entity.
. select the processing entity the tracing entity relates to.
. select various events of interest.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>