coresight-etm4x: Controls pertaining to the counter functions

Adding sysfs entries related to the counter functionality, more
specifically to set, control and reload the counters.

Change-Id: I0445a3e33bdee5d0a8c85ca69981007b3b4a19f1
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>
Git-commit: add2d5d0d15fe391e42b8b220590ed02ba0aad16
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Shashank Mittal <mittals@codeaurora.org>