CVE-2026-64290: iommufd: Break the loop on failure in iommufd_fault_fops_read()

In the Linux kernel, the following vulnerability has been resolved:

iommufd: Break the loop on failure in iommufdfaultfopsread()

On a copytouser() failure inside the inner listforeachentry, only the inner loop breaks; the outer while re-fetches the just-restored fault group and retries the failing copytouser() forever, spinning the reader at 100% CPU with fault->mutex held.

Check rc after the inner loop and break the outer while as well.