coresight: cti: Add CPU Hotplug handling to CTI driver

coresight: cti: Add CPU Hotplug handling to CTI driver

Adds registration of CPU start and stop functions to CPU hotplug
mechanisms - for any CPU bound CTI.

Sets CTI powered flag according to state.
Will enable CTI on CPU start if there are existing enable requests.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-23-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>