The legacy function qdev_reset_all() performs a recursive reset,
starting from a qdev.  However, it does not permit any of the devices
in the tree to use three-phase reset, because device reset goes
through the device_legacy_reset() function that only calls the single
DeviceClass::reset method.

Switch to using the device_cold_reset() function instead.  This also
performs a recursive reset, where first the children are reset and
then finally the parent, but it uses the new (...in 2020...)
Resettable mechanism, which supports both the old style single-reset
method and also the new 3-phase reset handling.

This commit changes the five remaining uses of this function.

Commit created with:
 sed -i -e 's/qdev_reset_all/device_cold_reset/g' hw/i386/xen/xen_platform.c hw/input/adb.c hw/remote/vfio-user-obj.c hw/s390x/s390-virtio-ccw.c hw/usb/dev-uas.c

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>