coresight-etm4x: Controls pertaining to tracer configuration

Tracers can be configured with various options at synthesis
time and knowing what resources are available is important for
SW configuration purposes.

As such adding RO sysfs entries for characteristics related to the
tracer implementation.

Change-Id: If528c1c0b3e87eaf3b66b50887e7e16e5288eb30
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: c0ddbfea722298db7fa66b921c30f2ee9190da04
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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