bus: arm-ccn: Prevent hotplug callback leak

bus: arm-ccn: Prevent hotplug callback leak

commit 26242b330093fd14c2e94fb6cbdf0f482ab26576 upstream.

In case the driver registration fails, the hotplug callback is leaked.

Not fatal, because it's never invoked as there are no instances registered,
but wrong nevertheless.

Fixes: fdc15a36d84e ("bus/arm-ccn: Convert to hotplug statemachine")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>