Claude review: drm/loongson: Use managed KMS polling

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Correctness: No issues.**

The change from:
```c
-	drm_kms_helper_poll_init(ddev);
+	drmm_kms_helper_poll_init(ddev);
```

is the right fix. `drmm_kms_helper_poll_init()` is declared in `drm/drm_probe_helper.h` and registers a managed cleanup action via `drmm_add_action_or_reset()`, so `drm_kms_helper_poll_fini()` is called automatically when the DRM device is released.

Looking at the probe function, the error paths at lines 300-301 and 308-310 return directly without any cleanup of the poll init — this patch fixes those leaks. The removal path in `lsdc_pci_remove()` also lacks a `drm_kms_helper_poll_fini()` call, which is likewise fixed by this change.

**Tags:** The patch has appropriate `Fixes:`, `Cc: stable`, `Reviewed-by` (Thomas Zimmermann, Huacai Chen), and `Acked-by` (Jianmin Lv) tags.

**Nit (non-blocking):** The return type of `drmm_kms_helper_poll_init()` is `void`, so there's no error to check — the current usage is correct.

**Verdict: Looks good.** No changes needed.

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Generated by Claude Code Patch Reviewer