Align naming convention of ClMatMul

Ensure naming of MatMul on GPU conforms to the naming convention <backend><operator><config> i.e. ClMatMul operator with the backend ClMatMulNativeKernel.

Resolves: COMPMID-6015

Change-Id: I021d235b023ad17fe97bd6913e6a50d0ba4b194e
Signed-off-by: Jakub Sujak <jakub.sujak@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9443
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/filelist.json b/filelist.json
index cf1c63b..5418c2b 100644
--- a/filelist.json
+++ b/filelist.json
@@ -512,7 +512,7 @@
     "MatMul": {
       "files": {
         "common": [
-          "src/gpu/cl/kernels/ClNativeMatMulKernel.cpp",
+          "src/gpu/cl/kernels/ClMatMulNativeKernel.cpp",
           "src/gpu/cl/operators/ClMatMul.cpp",
           "src/runtime/CL/functions/CLMatMul.cpp"
         ]