f2fs: fix to avoid f2fsbugon() in decvalidnode_count()
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 v5.18.3 by commit ccffa99ae6a1f44797b57444c6a80382a42928fe. For more details please see the references link.