[ET-VK] Tuning conv 2d pw op tile size to improve perf.

Pull Request resolved: #11112

This diff tunes the tile size for the conv 2d pw op to improve performance. The changes include updating the `TILE_SIZE_X` and `TILE_SIZE_Y` values in the `conv2d_pw.yaml` files and modifying the `Convolution.cpp` files to adjust the image extents calculation. The `TILE_SIZE_X` value is changed from 2 to 1, and the `TILE_SIZE_Y` value is changed from 2 to 4.
ghstack-source-id: 286439493

Differential Revision: [D75317820](https://our.internmc.facebook.com/intern/diff/D75317820/)

Author: trivedivivek

backends/vulkan/runtime/graph/ops/glsl/conv2d_pw.yaml

@@ -9,8 +9,8 @@ conv2d_pw:
     OPERATOR: X
     NDIM: 3
     DTYPE: float
-    TILE_SIZE_X: 2
-    TILE_SIZE_Y: 2
+    TILE_SIZE_X: 1
+    TILE_SIZE_Y: 4
   generate_variant_forall:
     DTYPE:
       - VALUE: half

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

@@ -305,8 +305,8 @@ utils::uvec3 create_conv2d_global_wg_size(
   if (method == Conv2dMethod::Pointwise) {
     const utils::uvec3 image_extents = graph.logical_limits_of(out);
     return {
-        utils::div_up(image_extents[0u], 2u),
-        utils::div_up(image_extents[1u], 2u),
+        utils::div_up(image_extents[0u], 1u),
+        utils::div_up(image_extents[1u], 4u),
         image_extents[2u]};
   } else if (method == Conv2dMethod::Depthwise && stride_equals_dilation) {
     const utils::uvec3 image_extents = graph.create_global_wg_size(out);