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/src/runtime/CL/functions/CLArithmeticAddition.cpp b/src/runtime/CL/functions/CLArithmeticAddition.cpp
index 5ca384d..5fa0b8c 100644
--- a/src/runtime/CL/functions/CLArithmeticAddition.cpp
+++ b/src/runtime/CL/functions/CLArithmeticAddition.cpp
@@ -36,3 +36,8 @@
     k->configure(input1, input2, output, policy);
     _kernel = std::move(k);
 }
+
+Error CLArithmeticAddition::validate(const ITensorInfo *input1, const ITensorInfo *input2, const ITensorInfo *output, ConvertPolicy policy)
+{
+    return CLArithmeticAdditionKernel::validate(input1, input2, output, policy);
+}