lasips2: update VMStateDescription for LASIPS2 device

lasips2: update VMStateDescription for LASIPS2 device

Since this series has already introduced a migration break for the HPPA B160L
machine, we can use this opportunity to improve the VMStateDescription for
the LASIPS2 device.

Add the new int_status field to the VMStateDescription and remodel the ports
as separate VMSTATE_STRUCT instances representing each LASIPS2Port. Once this
is done, the migration stream can be updated to include buf and loopback_rbne
for each port (which is necessary since the values are accessed across separate
IO accesses), and drop the port id as this is hardcoded for each port type.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Helge Deller <deller@gmx.de>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20220712215251.7944-35-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>