Then libbpf converts global data with SEC(".percpu") to global percpu
data. And bpftool generates struct for global percpu data like for
global data when generate skeleton.
Finally, verifier inserts a mov64_percpu_reg insn after the ld_imm64 in
order to add this_cpu_off to the dst_reg of ld_imm64.
Therefore, in check_ld_imm(), it should mark the dst_reg of ld_imm64 for
percpu array map as map-value-ptr.
Thanks,
Leon
