Claude review: arm64: dts: rockchip: rk3568-rock-3b: Enable NPU

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

Patch Review

This patch is clean and minimal:

```dts
&rknn_core_0 {
	npu-supply = <&vdd_npu>;
	status = "okay";
};

&rknn_mmu_0 {
	status = "okay";
};
```

No issues. The `vdd_npu` regulator is referenced from the existing board file. The pattern of enabling both the NPU core and its IOMMU is correct.

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**Summary of must-fix items:**
1. **Patch 2**: Fix the missing `$ref` in the `rockchip,pmu` property definition
2. **Patch 1**: Check `clk_set_rate()` return values in `rk3568_noc_init()`
3. **Patch 1**: Fix the incomplete error cleanup path after `noc_init` failure
4. **Patch 3**: Move NPU nodes to the correct address-sorted position

**Items worth discussing:**
- Runtime PM / system suspend re-initialization of the NOC bus
- Whether `rockchip,pmu` should be conditionally required in the binding
- The fragility of the two-step PVTPLL workaround

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Generated by Claude Code Patch Reviewer