Break up Utils.h a bit to reduce unused code being included everywhere

Move some maths-related things from Utils.h to new Math.h header in utils/math.
Move some routines used for Tensor shape validation to Validate.h

Change-Id: I8ce89fe03ec3ae1b61d1a80c282b8b91eea0cfb3
Signed-off-by: Matthew Bentham <Matthew.Bentham@arm.com>
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/c/VisualCompute/ComputeLibrary/+/524783
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Tested-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9743
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Jakub Sujak <jakub.sujak@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/gpu/cl/operators/ClActivation.h b/src/gpu/cl/operators/ClActivation.h
index 75b38e8..0942248 100644
--- a/src/gpu/cl/operators/ClActivation.h
+++ b/src/gpu/cl/operators/ClActivation.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited.
+ * Copyright (c) 2021, 2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -24,6 +24,7 @@
 #ifndef ARM_COMPUTE_CL_ACTIVATION_H
 #define ARM_COMPUTE_CL_ACTIVATION_H
 
+#include "arm_compute/core/ActivationLayerInfo.h"
 #include "src/gpu/cl/ClCompileContext.h"
 #include "src/gpu/cl/IClOperator.h"