tu/drm/virtio: Fix tu_wait_fence timeout handling

Fixes two bugs in the WAIT_FENCE polling loop:
1. Break on timeout returned VK_SUCCESS because ret was read too late.
2. UINT64_MAX timeout_ns overflowed end_time, causing immediate exit.

Fix by reading rsp->ret before the timeout check and using
OS_TIMEOUT_INFINITE (like virtio_pipe_wait in freedreno) to avoid
overflow.

This prevents premature BO teardown during host-side fault recovery.

Fixes: f17c5297d7 ("tu: Add virtgpu support")
Signed-off-by: Valentine Burley <valentine.burley@collabora.com>
(cherry picked from commit dad72b414b)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41269>

.pick_status.json

@@ -2494,7 +2494,7 @@
         "description": "tu/drm/virtio: Fix tu_wait_fence timeout handling",
         "nominated": true,
         "nomination_type": 2,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "f17c5297d7a01eb37815f96bbf3a87667a2f3261",
         "notes": null

src/freedreno/vulkan/tu_knl_drm_virtio.cc

@@ -427,10 +427,11 @@ tu_wait_fence(struct tu_device *dev,
       if (ret)
          goto out;
 
-      if (os_time_get_nano() >= end_time)
-         break;
-
       ret = rsp->ret;
+
+      if (timeout_ns != OS_TIMEOUT_INFINITE &&
+          os_time_get_nano() >= end_time)
+         break;
    } while (ret == -ETIMEDOUT);
 
 out: