venus: track dedicated image during mem alloc

Need this because the new common wsi interface only returns the wsi
memory from the acquired image index.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39401>
(cherry picked from commit 3fca8423c9)

.pick_status.json

@@ -3874,7 +3874,7 @@
         "description": "venus: track dedicated image during mem alloc",
         "nominated": false,
         "nomination_type": 0,
-        "resolution": 4,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/virtio/vulkan/vn_device_memory.h

@@ -48,6 +48,9 @@ struct vn_device_memory {
    uint64_t bo_roundtrip_seqno;
 
    VkDeviceSize map_end;
+
+   /* only valid when wsi platform is used */
+   struct vn_image *dedicated_img;
 };
 VK_DEFINE_NONDISP_HANDLE_CASTS(vn_device_memory,
                                base.vk.base,

src/virtio/vulkan/vn_wsi.c

@@ -243,6 +243,12 @@ vn_wsi_memory_info_init(struct vn_device_memory *mem,
       struct vn_buffer *buf = vn_buffer_from_handle(dedicated_info->buffer);
       buf->wsi.mem = mem;
    }
+
+   /* wsi_memory_allocate_info is not chained for prime blit src */
+   if (dedicated_info && dedicated_info->image != VK_NULL_HANDLE) {
+      struct vn_image *img = vn_image_from_handle(dedicated_info->image);
+      mem->dedicated_img = img;
+   }
 }
 
 static uint32_t