COMPMID-617: Add validation methods to ML CL functions.

Adds validation support to:
- CLDirectConvolution
- CLNormalizationLayer
- CLSoftmaxLayer

Change-Id: I9bd1e925e6db057c799169405f82ed21d20b87ee
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/95939
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
diff --git a/arm_compute/runtime/CL/functions/CLSoftmaxLayer.h b/arm_compute/runtime/CL/functions/CLSoftmaxLayer.h
index ab1b1ab..b5f1abc 100644
--- a/arm_compute/runtime/CL/functions/CLSoftmaxLayer.h
+++ b/arm_compute/runtime/CL/functions/CLSoftmaxLayer.h
@@ -58,6 +58,14 @@
      * @param[in]  beta   (Optional) A scaling factor for the exponent. Defaults to 1.f
      */
     void configure(const ICLTensor *input, ICLTensor *output, float beta = 1.0f);
+    /** Static function to check if given info will lead to a valid configuration of @ref CLSoftmaxLayer
+     *
+     * @param[in] input  Source tensor. Data types supported: QS8/QASYMM8/QS16/F16/F32
+     * @param[in] output Destination tensor. Data types supported: same as @p input
+     *
+     * @return an error status
+     */
+    static Error validate(const ITensorInfo *input, const ITensorInfo *output);
 
     // Inherited methods overridden:
     void run() override;