[ET-VK] Using TmpTensor for width packed versions of q_linear op shader to reduce memory usage.

This diff introduces the use of temporary tensors to reduce memory usage in the width packed versions of the q_linear op shader.

Differential Revision: [D68561647](https://our.internmc.facebook.com/intern/diff/D68561647/)

ghstack-source-id: 262822997
Pull Request resolved: #7929

Author: trivedivivek

backends/vulkan/runtime/graph/ops/impl/QuantizedLinear.cpp

@@ -73,13 +73,16 @@ void add_q_8w_linear_node(
   auto viewFn = VK_GET_OP_FN("aten.view_copy.default");
   ValueRef mat1_W_packed = mat1;
   ValueRef out_W_packed = out;
+  // Create temporary tensors to store the width packed versions of mat1 and out
+  TmpTensor mat1_tmp(&graph, graph.sizes_of(mat1), graph.dtype_of(mat1), utils::kWidthPacked);
+  TmpTensor out_tmp(&graph, graph.sizes_of(out), graph.dtype_of(out), utils::kWidthPacked);
   if (!graph.is_buffer_storage(out) &&
       graph.packed_dim_of(mat1) != WHCN::kWidthDim) {
     // Ensure mat1 is width packed
-    mat1_W_packed = graph.add_tensor_like(mat1, utils::kWidthPacked);
+    mat1_W_packed = mat1_tmp;
     viewFn(graph, {mat1, graph.add_none(), mat1_W_packed});
     // Ensure out is packed correctly
-    out_W_packed = graph.add_tensor_like(out, utils::kWidthPacked);
+    out_W_packed = out_tmp;
   }
   ValueRef q_mat2 = prepack_standard(
       graph, q_mat2_data, graph.storage_type_of(out), utils::kWidthPacked);