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/arm_compute/core/experimental/Types.h b/arm_compute/core/experimental/Types.h
index a009c0d..eca833e 100644
--- a/arm_compute/core/experimental/Types.h
+++ b/arm_compute/core/experimental/Types.h
@@ -34,7 +34,7 @@
 class ITensor;
 
 /** Memory type */
-enum class TensorType
+enum TensorType : int32_t
 {
     ACL_UNKNOWN = -1,
     ACL_SRC     = 0,
@@ -47,11 +47,12 @@
     ACL_INT     = 50,
     ACL_INT_0   = 50,
     ACL_INT_1   = 51,
-    ACL_INT_2   = 52
+    ACL_INT_2   = 52,
+    ACL_SRC_VEC = 256,
 };
 
-using InputTensorMap    = std::map<TensorType, const ITensor *>;
-using OutputTensorMap   = std::map<TensorType, ITensor *>;
+using InputTensorMap    = std::map<int32_t, const ITensor *>;
+using OutputTensorMap   = std::map<int32_t, ITensor *>;
 using OperatorTensorMap = OutputTensorMap;
 
 namespace experimental