CVE-2023-54283 bpf: Address KCSAN report on bpf_lru_list

In the Linux kernel, the following vulnerability has been resolved: bpf: Address KCSAN report on bpflrulist KCSAN reported a data-race when accessing node-ref. Although node-ref does not have to be accurate, take this chance to use a more common READONCE and WRITEONCE pattern instead of datarace...