iio: fix memory leak in iiodeviceregister_eventset()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.86 by commit dc6afd6070f3a5b086c8c5cfa6ded63ae44494da, it was introduced in version v5.13 by commit 32f171724e5cbecc80594fb6eced057cfdd6eb6f. For more details please see the references link.