Fix Doxygen references

Some references are no longer valid because the kernels/functions have
been removed.

Change-Id: Iccfaabb678a4b2709442e4eb827800e63ea47b05
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4764
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/runtime/CL/functions/CLBitwiseNot.h b/arm_compute/runtime/CL/functions/CLBitwiseNot.h
index 1d8531a..6f65749 100644
--- a/arm_compute/runtime/CL/functions/CLBitwiseNot.h
+++ b/arm_compute/runtime/CL/functions/CLBitwiseNot.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2020 Arm Limited.
+ * Copyright (c) 2016-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -31,7 +31,7 @@
 class CLCompileContext;
 class ICLTensor;
 
-/** Basic function to run @ref CLBitwiseNotKernel.
+/** Basic function to perform bitwise NOT by running @ref CLBitwiseKernel.
  *
  * @note The tensor data type for the inputs must be U8.
  * @note The function performs a bitwise NOT operation on input tensor.