[BE][MPS] Delete unused complex_mul_out (pytorch#154175)

It's no longer called, after `mul` has been migrated to binary op
Pull Request resolved: pytorch#154175
Approved by: https://github.com/dcci, https://github.com/Skylion007

Author: malfet

aten/src/ATen/native/mps/operations/BinaryKernel.h

@@ -7,8 +7,4 @@ void binary_op_kernel(
     const Tensor& other,
     const Tensor& output,
     const std::optional<Scalar> alpha = std::nullopt);
-void complex_mul_out(
-    const Tensor& input,
-    const Tensor& other,
-    const Tensor& output);
 } // namespace at::native::mps

aten/src/ATen/native/mps/operations/BinaryKernel.mm

@@ -33,24 +33,6 @@
 
 namespace mps {
 
-void complex_mul_out(const Tensor& input, const Tensor& other, const Tensor& output) {
-  TORCH_INTERNAL_ASSERT(c10::isComplexType(input.scalar_type()) || c10::isComplexType(other.scalar_type()));
-  auto new_size = at::infer_size(input.sizes(), other.sizes());
-  if (!output.sizes().equals(new_size)) {
-    output.resize_(new_size);
-  }
-  uint32_t length = output.numel();
-  if (length == 0) {
-    return;
-  }
-  auto common_dtype = output.scalar_type();
-  auto input_cast = input.to(kMPS, common_dtype);
-  auto other_cast = other.to(kMPS, common_dtype);
-  auto iter = TensorIteratorConfig().add_output(output).add_input(input_cast).add_input(other_cast).build();
-
-  lib.exec_binary_kernel(iter, "complex_mul");
-}
-
 void binary_op_kernel(const std::string func_name,
                       const Tensor& input,
                       const Tensor& other,