coresight: cti: Add sysfs access to program function registers

coresight: cti: Add sysfs access to program function registers

Adds in sysfs programming support for the CTI function register sets.
Allows direct manipulation of channel / trigger association registers.

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/20200320165303.13681-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>