Break up core/Utils.h to reduce unused code being included everywhere

Makes a small difference to compile times and opens up other opportunities
to simplify code.

Change-Id: I232876910bbe4fa9719f4a0ce4a54c090faeb5ef
Signed-off-by: Matthew Bentham <Matthew.Bentham@arm.com>
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/c/VisualCompute/ComputeLibrary/+/532429
Tested-by: bsgcomp <bsgcomp@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9856
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/gpu/cl/kernels/ClActivationKernel.h b/src/gpu/cl/kernels/ClActivationKernel.h
index 95e0108..5369c95 100644
--- a/src/gpu/cl/kernels/ClActivationKernel.h
+++ b/src/gpu/cl/kernels/ClActivationKernel.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021 Arm Limited.
+ * Copyright (c) 2016-2021, 2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -24,6 +24,7 @@
 #ifndef ARM_COMPUTE_CL_ACTIVATION_KERNEL_H
 #define ARM_COMPUTE_CL_ACTIVATION_KERNEL_H
 
+#include "arm_compute/core/ActivationLayerInfo.h"
 #include "src/core/common/Macros.h"
 #include "src/gpu/cl/ClCompileContext.h"
 #include "src/gpu/cl/IClKernel.h"