venus: force async pipeline create on threads creating descriptor pools

This works around some Unity engine behaivor with ANGLE-on-Venus, when
cmd pools are created on main thread once while the render thread only
does descriptor pool creation for set allocations during recording time.

This change also explicitly forces async pipeline create for threads
creating the device instead of implicitly via feedback cmd pool create.
This ensures intended behavior when feedback is disabled.

Fixes: d17ddcc847 ("venus: dispatch background shader tasks to secondary ring")
Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27347>
(cherry picked from commit 1718980e851c1cfaba80098bcd10915a7522e882)

.pick_status.json

@@ -11884,7 +11884,7 @@
         "description": "venus: force async pipeline create on threads creating descriptor pools",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "d17ddcc84773899ef8b022d94969ffc0909db0bc",
         "notes": null

src/virtio/vulkan/vn_descriptor_set.c

@@ -390,6 +390,8 @@ vn_CreateDescriptorPool(VkDevice device,
    vn_async_vkCreateDescriptorPool(dev->primary_ring, device, pCreateInfo,
                                    NULL, &pool_handle);
 
+   vn_tls_set_async_pipeline_create();
+
    *pDescriptorPool = pool_handle;
 
    return VK_SUCCESS;

src/virtio/vulkan/vn_device.c

@@ -570,6 +570,8 @@ vn_CreateDevice(VkPhysicalDevice physicalDevice,
       vn_log(instance, "%s", physical_dev->properties.vulkan_1_2.driverInfo);
    }
 
+   vn_tls_set_async_pipeline_create();
+
    *pDevice = vn_device_to_handle(dev);
 
    return VK_SUCCESS;