coresight: pmu: Adding ITRACE property to cs_etm PMU

Add to the capabilities the ITRACE property so that ITRACE START events
are generated when the PMU is switched on by the core.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>