Add the vmstate for the new NeXTPC devic; this is in theory
a migration compatibility break, but this machine doesn't have
working migration currently anyway.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20210115201206.17347-11-peter.maydell@linaro.org>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>