hw/core/resetcontainer: Consolidate OBJECT_DECLARE_SIMPLE_TYPE

hw/core/resetcontainer: Consolidate OBJECT_DECLARE_SIMPLE_TYPE

The QOM type of ResettableContainer is defined by
OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES, which means it doesn't need
the class!

Therefore, use OBJECT_DECLARE_SIMPLE_TYPE to declare the type, then
there's no need for class definition.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250514084957.2221975-8-zhao1.liu@intel.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>