Rename PixelwiseMultiplications to Mul for simplicity

Changes the names of the following:
 - PixelWiseMultiplicationKernel to MulKernel for all backends
 - PixelWiseMultiplication to Mul for all backends

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I88108c2d22c888fce37ea1028863026160b9da97
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5534
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/runtime/CL/functions/CLPixelWiseMultiplication.cpp b/src/runtime/CL/functions/CLPixelWiseMultiplication.cpp
index efebf2b..9326592 100644
--- a/src/runtime/CL/functions/CLPixelWiseMultiplication.cpp
+++ b/src/runtime/CL/functions/CLPixelWiseMultiplication.cpp
@@ -26,7 +26,7 @@
 #include "arm_compute/core/CL/ICLTensor.h"
 #include "arm_compute/runtime/CL/CLScheduler.h"
 #include "src/core/CL/ICLKernel.h"
-#include "src/runtime/gpu/cl/operators/ClPixelWiseMultiplication.h"
+#include "src/runtime/gpu/cl/operators/ClMul.h"
 
 #include <utility>
 
@@ -34,10 +34,10 @@
 {
 struct CLPixelWiseMultiplication::Impl
 {
-    const ICLTensor                                   *src_0{ nullptr };
-    const ICLTensor                                   *src_1{ nullptr };
-    ICLTensor                                         *dst{ nullptr };
-    std::unique_ptr<opencl::ClPixelWiseMultiplication> op{ nullptr };
+    const ICLTensor               *src_0{ nullptr };
+    const ICLTensor               *src_1{ nullptr };
+    ICLTensor                     *dst{ nullptr };
+    std::unique_ptr<opencl::ClMul> op{ nullptr };
 };
 
 CLPixelWiseMultiplication::CLPixelWiseMultiplication()
@@ -60,14 +60,14 @@
     _impl->src_0 = input1;
     _impl->src_1 = input2;
     _impl->dst   = output;
-    _impl->op    = std::make_unique<opencl::ClPixelWiseMultiplication>();
+    _impl->op    = std::make_unique<opencl::ClMul>();
     _impl->op->configure(compile_context, input1->info(), input2->info(), output->info(), scale, overflow_policy, rounding_policy, act_info);
 }
 
 Status CLPixelWiseMultiplication::validate(const ITensorInfo *input1, const ITensorInfo *input2, const ITensorInfo *output, float scale,
                                            ConvertPolicy overflow_policy, RoundingPolicy rounding_policy, const ActivationLayerInfo &act_info)
 {
-    return opencl::ClPixelWiseMultiplication::validate(input1, input2, output, scale, overflow_policy, rounding_policy, act_info);
+    return opencl::ClMul::validate(input1, input2, output, scale, overflow_policy, rounding_policy, act_info);
 }
 
 void CLPixelWiseMultiplication::run()
@@ -82,10 +82,10 @@
 
 struct CLComplexPixelWiseMultiplication::Impl
 {
-    const ICLTensor                                          *src_0{ nullptr };
-    const ICLTensor                                          *src_1{ nullptr };
-    ICLTensor                                                *dst{ nullptr };
-    std::unique_ptr<opencl::ClComplexPixelWiseMultiplication> op{ nullptr };
+    const ICLTensor                      *src_0{ nullptr };
+    const ICLTensor                      *src_1{ nullptr };
+    ICLTensor                            *dst{ nullptr };
+    std::unique_ptr<opencl::ClComplexMul> op{ nullptr };
 };
 
 CLComplexPixelWiseMultiplication::CLComplexPixelWiseMultiplication()
@@ -106,13 +106,13 @@
     _impl->src_0 = input1;
     _impl->src_1 = input2;
     _impl->dst   = output;
-    _impl->op    = std::make_unique<opencl::ClComplexPixelWiseMultiplication>();
+    _impl->op    = std::make_unique<opencl::ClComplexMul>();
     _impl->op->configure(compile_context, input1->info(), input2->info(), output->info(), act_info);
 }
 
 Status CLComplexPixelWiseMultiplication::validate(const ITensorInfo *input1, const ITensorInfo *input2, const ITensorInfo *output, const ActivationLayerInfo &act_info)
 {
-    return opencl::ClComplexPixelWiseMultiplication::validate(input1, input2, output, act_info);
+    return opencl::ClComplexMul::validate(input1, input2, output, act_info);
 }
 
 void CLComplexPixelWiseMultiplication::run()