COMPMID-3374: Remove memory state from  NEConcatenateLayer kernels

* Allow the following kernels to accept backing memory at run-time:
  * NEBatchConcatenateLayerKernel
  * NEDepthConcatenateLayerKernel
  * NEHeightConcatenateLayerKernel
  * NEWidthConcatenateLayerKernel
* Allow the following functions to accept backing memory at run-time:
  * NEConcatenateLayer

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: Ib0b6714cff7f06a52dc74d294bc3e0d72a1c2419
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/3569
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/NEON/BatchConcatenateLayer.cpp b/tests/validation/NEON/BatchConcatenateLayer.cpp
index bd8d0dc..6eafe82 100644
--- a/tests/validation/NEON/BatchConcatenateLayer.cpp
+++ b/tests/validation/NEON/BatchConcatenateLayer.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 Arm Limited.
+ * Copyright (c) 2019-2020 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -70,7 +70,7 @@
     inputs_vector_info.emplace_back(std::move(input_info1));
     inputs_vector_info.emplace_back(std::move(input_info2));
 
-    std::vector<ITensorInfo *> inputs_vector_info_raw;
+    std::vector<const ITensorInfo *> inputs_vector_info_raw;
     inputs_vector_info_raw.reserve(inputs_vector_info.size());
     for(auto &input : inputs_vector_info)
     {