hw/core/reset: Add qemu_{register, unregister}_resettable()

hw/core/reset: Add qemu_{register, unregister}_resettable()

Implement new functions qemu_register_resettable() and
qemu_unregister_resettable().  These are intended to be
three-phase-reset aware equivalents of the old qemu_register_reset()
and qemu_unregister_reset().  Instead of passing in a function
pointer and opaque, you register any QOM object that implements the
Resettable interface.

The implementation is simple: we have a single global instance of a
ResettableContainer, which we reset in qemu_devices_reset(), and
the Resettable objects passed to qemu_register_resettable() are
added to it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20240220160622.114437-8-peter.maydell@linaro.org
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>