hw: Define new device_class_set_legacy_reset()

hw: Define new device_class_set_legacy_reset()

Define a device_class_set_legacy_reset() function which
sets the DeviceClass::reset field. This serves two purposes:
 * it makes it clearer to the person writing code that
   DeviceClass::reset is now legacy and they should look for
   the new alternative (which is Resettable)
 * it makes it easier to rename the reset field (which in turn
   makes it easier to find places that call it)

The Coccinelle script can be used to automatically convert code that
was doing an open-coded assignment to DeviceClass::reset to call
device_class_set_legacy_reset() instead.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240830145812.1967042-7-peter.maydell@linaro.org