Fix 'ARM_DOT_K0XN0' macro redefined

Resolve COMPMID-4339

Change-Id: Ieacd288ca8f69e04d88692a093325a24198ebe3e
Signed-off-by: Giorgio Arena <giorgio.arena@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5623
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/CL/cl_kernels/gemm.cl b/src/core/CL/cl_kernels/gemm.cl
index 6883aaf..10435d3 100644
--- a/src/core/CL/cl_kernels/gemm.cl
+++ b/src/core/CL/cl_kernels/gemm.cl
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020 Arm Limited.
+ * Copyright (c) 2017-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -2460,6 +2460,10 @@
 #endif // K0 conditions
 #endif // defined(MIXED_PRECISION)
 
+#if defined(ARM_DOT_K0XN0)
+#undef ARM_DOT_K0XN0
+#endif // defined(ARM_DOT_K0XN0)
+
 #if N0 == 2
 #define ARM_DOT_K0XN0(a, b, c)           \
     ({                                   \