macfb: add VMStateDescription fields for display type and VBL timer

These fields are required in the migration stream to restore macfb state
correctly.

Note this is a migration break, but since there are upcoming incompatible changes
for the q800 machine (and migration does not even succeed without these patches)
then this is not an issue.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220305155530.9265-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

hw/display/macfb.c

@@ -625,9 +625,11 @@ static const VMStateDescription vmstate_macfb = {
     .minimum_version_id = 1,
     .post_load = macfb_post_load,
     .fields = (VMStateField[]) {
+        VMSTATE_UINT8(type, MacfbState),
         VMSTATE_UINT8_ARRAY(color_palette, MacfbState, 256 * 3),
         VMSTATE_UINT32(palette_current, MacfbState),
         VMSTATE_UINT32_ARRAY(regs, MacfbState, MACFB_NUM_REGS),
+        VMSTATE_TIMER_PTR(vbl_timer, MacfbState),
         VMSTATE_END_OF_LIST()
     }
 };