qxl: reload memslots after migration, when qxl is in UNDEFINED mode

The devram memslot stays active when qxl enters UNDEFINED mode (i.e, no
primary surface). If migration has occurred while the device is in
UNDEFINED stae, the memslots have to be reloaded at the destination.

Fixes rhbz#874574

Signed-off-by: Yonit Halperin <yhalperi@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit fa98efe)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

hw/qxl.c

@@ -2042,6 +2042,7 @@ static int qxl_post_load(void *opaque, int version)
 
     switch (newmode) {
     case QXL_MODE_UNDEFINED:
+        qxl_create_memslots(d);
         break;
     case QXL_MODE_VGA:
         qxl_create_memslots(d);