coresight: Rearrange platform data probing

We are about to introduce methods to clean up the platform data
as we switch to tracking the device reference from "name" to "fwnode
handles" for device connections. This requires us to drop the fwnode
handle references when the data is no longer required - i.e, when
the device probe fails or the device gets unregistered.

In order to consolidate the invocation of the cleanup, we delay the
platform probing to the very last minute, possibly before invoking
the coresight_register. Then, we leave the coresight core code to
do the clean up. i.e, if the coresight_register fails, it takes
care of freeing the data. Otherwise, coresight_unregister will
do the necessary operations.

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>