CVE-2025-22114 btrfs: don't clobber ret in btrfs_validate_super()

In the Linux kernel, the following vulnerability has been resolved: btrfs: don't clobber ret in btrfsvalidatesuper Commit 2a9bb78cfd36 "btrfs: validate system chunk array at btrfsvalidatesuper" introduces a call to validatesyschunkarray in btrfsvalidatesuper, which clobbers the value of ret set...