Claude review: drm/xe/i2c: use platform_device_add_software_node()

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

Patch Review

The static software node definition is clean:
```c
static const struct software_node xe_i2c_adapter_swnode = {
    .properties = xe_i2c_adapter_properties,
};
```

And the call to `platform_device_add_software_node()` is correct.

**Bug 1: Uninitialized variable `fwnode` assigned to `i2c->adapter_node`.**

The patch removes the assignment `fwnode = fwnode_create_software_node(...)` but leaves both the declaration `struct fwnode_handle *fwnode;` and the line:
```c
i2c->adapter_node = fwnode;
```

After the patch, `fwnode` is declared but never assigned, so `i2c->adapter_node` receives an uninitialized pointer. The compiler should warn about this.

**Bug 2: `xe_i2c_unregister_adapter()` is not updated.**

The current unregister function:
```c
static void xe_i2c_unregister_adapter(struct xe_i2c *i2c)
{
    platform_device_unregister(i2c->pdev);
    fwnode_remove_software_node(i2c->adapter_node);
}
```

After patch 5 adds `device_remove_software_node()` to the release callback, the swnode is freed during `platform_device_unregister()`. The subsequent `fwnode_remove_software_node(i2c->adapter_node)` would be a use-after-free (compounded by the uninitialized pointer from bug 1).

The fix should:
1. Remove the `struct fwnode_handle *fwnode;` declaration (now unused).
2. Remove the `i2c->adapter_node = fwnode;` line.
3. Update `xe_i2c_unregister_adapter()` to remove the `fwnode_remove_software_node()` call, since the release callback now handles cleanup.

If `i2c->adapter_node` is used elsewhere, it should be set to `software_node_fwnode(&xe_i2c_adapter_swnode)` instead.

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Generated by Claude Code Patch Reviewer