Claude review: drm/xe/ras: Set error threshold support

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

Patch Review

Implements `xe_ras_set_threshold()` with the set-threshold mailbox command and adds RAS operation status codes.

**Positive: Good status code handling.** The `ras_status_to_errno()` function properly maps firmware status codes to standard errno values, including a catch-all `-EPROTO` for unexpected statuses.

**Minor: Stray semicolon after function definition.**

```c
static int ras_status_to_errno(u32 status)
{
    ...
    }
};   // <-- spurious semicolon
```

This compiles but is technically a stray empty declaration. Harmless but not clean.

**Same bounds-checking concern as patch 5** applies to `xe_ras_set_threshold()`.

**Observation: `get_threshold` does not check `response.status` but `set_threshold` does.** If the firmware can return a non-zero status for get operations too, the get path may silently return garbage data. Worth checking whether the get response also has a status field — looking at `xe_ras_get_threshold_response`, it does not have a `status` field, so this is fine.

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Generated by Claude Code Patch Reviewer