COMPMID-617: Add validation functions.

Added validation routines to the following kernels.
-CLActivationLayer
-CLBatchNormalizationLayer
-CLArithmeticAddition
-CLArithmeticSubtraction
-CLPixelwiseMultiplication

Change-Id: I0f3a03154f9e392279f715af656683cd0ad4cef5
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/94595
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
diff --git a/arm_compute/core/CL/kernels/CLPoolingLayerKernel.h b/arm_compute/core/CL/kernels/CLPoolingLayerKernel.h
index 29190e2..a9159a4 100644
--- a/arm_compute/core/CL/kernels/CLPoolingLayerKernel.h
+++ b/arm_compute/core/CL/kernels/CLPoolingLayerKernel.h
@@ -60,11 +60,11 @@
     void configure(const ICLTensor *input, ICLTensor *output, const PoolingLayerInfo &pool_info);
     /** Static function to check if given info will lead to a valid configuration of @ref CLPoolingLayerKernel
      *
-     * @param[in] input     Input's tensor info
-     * @param[in] output    Output's tensor info
+     * @param[in] input     Source tensor info. Data types supported: QS8/QS16/F16/F32.
+     * @param[in] output    Destination tensor info. Data types supported: Same as @p input.
      * @param[in] pool_info Contains pooling operation information described in @ref PoolingLayerInfo.
      *
-     * @return an error
+     * @return an error status
      */
     static Error validate(const ITensorInfo *input, const ITensorInfo *output, const PoolingLayerInfo &pool_info);