coresight: Add support for releasing platform specific data

Add a helper to clean up the platform specific data provided
by the firmware. This will be later used for dropping the necessary
references when we switch to the fwnode handles for tracking
connections.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>