Fix rank 0 support in serialization_lib

Numpy rank 0 files correctly written as shape () instead of (1)
Constant tensors of rank 0 now have data written out

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: Ie4bad8f798674cdb0484955e9db684f7f4100145
diff --git a/python/serializer/tosa_serializer.py b/python/serializer/tosa_serializer.py
index 9658edf..e6ab3d0 100644
--- a/python/serializer/tosa_serializer.py
+++ b/python/serializer/tosa_serializer.py
@@ -407,12 +407,15 @@
         if isinstance(data, np.ndarray):
             data = data.flatten().astype(fntype).tolist()
             data = list(map(fntype, data))
-            self.data = data
         elif isinstance(data, list):
             data = list(map(fntype, data))
-            self.data = data
+        elif data is not None:
+            # Assume data is rank 0 data type
+            data = list(map(fntype, [data]))
         else:
-            self.data = None
+            data = None
+
+        self.data = data
 
         # Filename for placeholder tensors.  These get generated by the test generation
         # process and are written to disk, but are considered input tensors by the