coresight: cti: Add sysfs trigger / channel programming API

coresight: cti: Add sysfs trigger / channel programming API

Adds a user API to allow programming of CTI by trigger ID and
channel number. This will take the channel and trigger ID supplied
by the user and program the appropriate register values.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200320165303.13681-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>