Add mean.dtype_out op for Ads model

Summary: title

Differential Revision: D67453766

Author: David Lin

kernels/aten/functions.yaml

@@ -257,6 +257,8 @@
 
 - op: mean.out
 
+- op: mean.dtype_out
+
 - op: min.dim_min
 
 - op: min.unary_out

kernels/portable/cpu/op_mean.cpp

@@ -66,6 +66,14 @@ Tensor& mean_dim_out(
   return out;
 }
 
+Tensor& mean_dtype_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& in,
+    optional<ScalarType> dtype,
+    Tensor& out) {
+  return mean_dim_out(ctx, in, ArrayRef<int64_t>(), false, dtype, out);
+}
+
 } // namespace native
 } // namespace executor
 } // namespace torch

kernels/portable/functions.yaml

@@ -577,6 +577,11 @@
     - arg_meta: null
       kernel_name: torch::executor::mean_dim_out
 
+- op: mean.dtype_out
+  kernels:
+    - arg_meta: null
+      kernel_name: torch::executor::mean_dtype_out
+
 - op: min.dim_min
   kernels:
     - arg_meta: null