Claude review: moduleparam: Route DEFINE_KERNEL_PARAM_OPS get pointer via _Generic

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

Patch Review

This is the key migration enabler. The `_Generic` dispatch:

```c
+#define _KERNEL_PARAM_OPS_GET(_get)					\
+	_Generic((_get),						\
+	    int (*)(char *, const struct kernel_param *): NULL,		\
+	    default: (_get))
```

When `_get` has the legacy `char *` signature, `_KERNEL_PARAM_OPS_GET` yields NULL (and `_KERNEL_PARAM_OPS_GET_STR` yields the pointer via `default`). When `_get` has the new `seq_buf *` signature, the opposite. If `_get` matches neither signature, the `default` branch still fires but the assignment to the struct field produces a type mismatch compile error.

**Minor observation:** The `_Generic` selectors use two explicit types plus `default`. If someone passes a `NULL` literal for `_get`, `_Generic` on a null pointer constant may have implementation-defined behavior across compilers. However, passing NULL for `_get` in these macros is unlikely in practice (you'd just omit `.get`), and the existing uses all pass actual function pointers.

**Verdict: Clever and correct approach for the migration period.**

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Generated by Claude Code Patch Reviewer