hw/ide/microdrive: Use device_cold_reset() for self-resets

hw/ide/microdrive: Use device_cold_reset() for self-resets

Currently the microdrive code uses device_legacy_reset() to reset
itself, and has its reset method call reset on the IDE bus as the
last thing it does.  Switch to using device_cold_reset().

The only concrete microdrive device is the TYPE_DSCM1XXXX; it is not
command-line pluggable, so it is used only by the old pxa2xx Arm
boards 'akita', 'borzoi', 'spitz', 'terrier' and 'tosa'.

You might think that this would result in the IDE bus being
reset automatically, but it does not, because the IDEBus type
does not set the BusClass::reset method. Instead the controller
must explicitly call ide_bus_reset(). We therefore leave that
call in md_reset().

Note also that because the PCMCIA card device is a direct subclass of
TYPE_DEVICE and we don't model the PCMCIA controller-to-card
interface as a qbus, PCMCIA cards are not on any qbus and so they
don't get reset when the system is reset.  The reset only happens via
the dscm1xxxx_attach() and dscm1xxxx_detach() functions during
machine creation.

Because our aim here is merely to try to get rid of calls to the
device_legacy_reset() function, we leave these other dubious
reset-related issues alone.  (They all stem from this code being
absolutely ancient.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20221013174042.1602926-1-peter.maydell@linaro.org