COMPMID-802 Add NHWC data format support for NEON im2col.

Change-Id: I86e678179106a2b83d1c6a7cfe562df91b0f9eb2
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/124000
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
diff --git a/tests/validation/reference/FlattenLayer.h b/tests/validation/reference/FlattenLayer.h
index b1286fe..5ccd429 100644
--- a/tests/validation/reference/FlattenLayer.h
+++ b/tests/validation/reference/FlattenLayer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 ARM Limited.
+ * Copyright (c) 2017-2018 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -36,7 +36,7 @@
 namespace reference
 {
 template <typename T>
-SimpleTensor<T> flatten_layer(const SimpleTensor<T> &src);
+SimpleTensor<T> flatten_layer(const SimpleTensor<T> &src, const TensorShape &shape_flatten);
 } // namespace reference
 } // namespace validation
 } // namespace test