gve: Add NULL pointer checks when freeing irqs.
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 v5.4.124 by commit 821149ee88c206fa37e79c1868cc270518484876, it was introduced in version v5.3 by commit 893ce44df56580fb878ca5af9c4a5fd87567da50. For more details please see the references link.