platform/x86: lenovo-wmi-helpers: Fix memory leak in lwmi_dev_evaluate_int()

lwmi_dev_evaluate_int() leaks output.pointer when retval == NULL (found
by sashiko.dev [1]).

Fix it by moving `ret_obj = output.pointer' outside of the `if (retval)'
block so that it is always freed by the __free cleanup callback.

No functional change intended.

Fixes: e521d16 ("platform/x86: Add lenovo-wmi-helpers")
Cc: stable@vger.kernel.org
Link: https://sashiko.dev/#/patchset/20260331181208.421552-1-derekjohn.clark%40gmail.com [1]
Signed-off-by: Rong Zhang <i@rong.moe>

Author: Rongronggg9

drivers/platform/x86/lenovo/wmi-helpers.c

@@ -55,8 +55,9 @@ int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
 	if (ACPI_FAILURE(status))
 		return -EIO;
 
+	ret_obj = output.pointer;
+
 	if (retval) {
-		ret_obj = output.pointer;
 		if (!ret_obj)
 			return -ENODATA;