Fix doxygen references to new kernels

Resolves COMPMID-4117

Change-Id: I9945a92402e34b9cfe0ba9ef2a961b168bf62721
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4883
Reviewed-by: Pablo Marquez Tello <pablo.tello@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/runtime/cpu/operators/CpuActivation.h b/src/runtime/cpu/operators/CpuActivation.h
index a357b32..0ae16bf 100644
--- a/src/runtime/cpu/operators/CpuActivation.h
+++ b/src/runtime/cpu/operators/CpuActivation.h
@@ -30,7 +30,7 @@
 {
 namespace cpu
 {
-/** Basic function to run @ref CpuActivationKernel */
+/** Basic function to run @ref kernels::CpuActivationKernel */
 class CpuActivation : public ICpuOperator
 {
 public:
@@ -43,7 +43,7 @@
      * @param[in]  activation_info Activation layer parameters.
      */
     void configure(const ITensorInfo *input, ITensorInfo *output, const ActivationLayerInfo &activation_info);
-    /** Static function to check if given info will lead to a valid configuration of @ref NEActivationLayer
+    /** Static function to check if given info will lead to a valid configuration of @ref CpuActivation
      *
      * @param[in] input    Source tensor info. Data types supported: QASYMM8/QASYMM8_SIGNED/QSYMM16/F16/F32.
      * @param[in] output   Destination tensor info. Data type supported: same as @p src