Claude review: treewide: Convert custom kernel_param_ops .get callbacks to seq_buf via cocci

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

Patch Review

Coccinelle-generated conversions of callbacks that end with a single `scnprintf`/`sprintf`/`sysfs_emit` return. The Coccinelle rule is shown and is correct.

**Bug: `drivers/acpi/ec.c` `param_get_event_clearing`** — The converted code has an unreachable `return 0;` after the switch:

```c
+	default:
+		seq_buf_printf(buffer, "invalid\n");
+		return 0;
	}
	return 0;
 }
```

Since every case (including `default`) now returns 0 explicitly, the `return 0;` after the closing `}` of the switch is dead code. This isn't a bug per se (it was already dead code in the original with the `return sprintf(...)` statements), but the Coccinelle script didn't clean it up. The compiler will likely elide it. **Cosmetic only.**

The `drm_panic.c` change is straightforward:

```c
-static int drm_panic_type_get(char *buffer, const struct kernel_param *kp)
+static int drm_panic_type_get(struct seq_buf *buffer,
+			      const struct kernel_param *kp)
 {
-	return scnprintf(buffer, PAGE_SIZE, "%s\n",
-			 drm_panic_type_map[drm_panic_type]);
+	seq_buf_printf(buffer, "%s\n", drm_panic_type_map[drm_panic_type]);
+	return 0;
 }
```

Correct.

**Verdict: Mechanical, correct. One cosmetic dead-code artifact in `drivers/acpi/ec.c`.**

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Generated by Claude Code Patch Reviewer