Drop the power handle only if we were successful. Otherwise
the AMBA bus code would do the rest.

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