UPSTREAM: coresight: tmc: Cleanup power management

Drop the power only if we were successful in probing the device.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
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>

(Upstream commit 263556950f2ad764bad4f98fbc5a9d711fd653a6).

Bug: 140266694
Change-Id: I8f53b3ef0d438b01c53e8132360f776b0171704e
Signed-off-by: Yabin Cui <yabinc@google.com>