HID: magicmouse: avoid memory leak in magicmouse_report_fixup()

The magicmouse_report_fixup() function was returning a
newly kmemdup()-allocated buffer, but never freeing it.

The caller of report_fixup() does not take ownership of the returned
pointer, but it *is* permitted to return a sub-portion of the input
rdesc, whose lifetime is managed by the caller.

Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Günther Noack <gnoack@google.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

Author: gnoack

drivers/hid/hid-magicmouse.c

@@ -994,9 +994,7 @@ static const __u8 *magicmouse_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 		hid_info(hdev,
 			 "fixing up magicmouse battery report descriptor\n");
 		*rsize = *rsize - 1;
-		rdesc = kmemdup(rdesc + 1, *rsize, GFP_KERNEL);
-		if (!rdesc)
-			return NULL;
+		rdesc = rdesc + 1;
 
 		rdesc[0] = 0x05;
 		rdesc[1] = 0x01;