vmstate-static-checker: Recognize "num" field

Recognize this field for VMS_ARRAY typed vmsd fields, then we can do proper
size matching with previous patch.

Note that this is compatible with old -dump-vmstate output, because when
"num" is not there we'll still use the old "size" only.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

scripts/vmstate-static-checker.py

@@ -134,6 +134,11 @@ def exists_in_substruct(fields, item):
     return check_fields_match(fields["Description"]["name"],
                               substruct_fields[0]["field"], item)
 
+def size_total(entry):
+    size = entry["size"]
+    if "num" not in entry:
+        return size
+    return size * entry["num"]
 
 def check_fields(src_fields, dest_fields, desc, sec):
     # This function checks for all the fields in a section.  If some
@@ -249,17 +254,19 @@ def check_fields(src_fields, dest_fields, desc, sec):
                 continue
 
             if s_item["field"] == "unused" or d_item["field"] == "unused":
-                if s_item["size"] == d_item["size"]:
+                s_size = size_total(s_item)
+                d_size = size_total(d_item)
+                if s_size == d_size:
                     continue
 
                 if d_item["field"] == "unused":
                     advance_dest = False
-                    unused_count = d_item["size"] - s_item["size"]
+                    unused_count = d_size - s_size;
                     continue
 
                 if s_item["field"] == "unused":
                     advance_src = False
-                    unused_count = s_item["size"] - d_item["size"]
+                    unused_count = s_size - d_size
                     continue
 
             print("Section \"" + sec + "\",", end=' ')