stellaris: delay timer_new to avoid memleaks

stellaris: delay timer_new to avoid memleaks

There is a memory leak when we call 'device_list_properties' with typename = stellaris-gptm. It's easy to reproduce as follow:

  virsh qemu-monitor-command vm1 --pretty '{"execute": "device-list-properties", "arguments": {"typename": "stellaris-gptm"}}'

This patch delay timer_new in realize to fix it.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200205070659.22488-4-pannengyuan@huawei.com
Cc: qemu-arm@nongnu.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>