bpf: name unnamed bpf programs
    
    bpf-firewall and bpf-devices do not have names. This complicates
    debugging with bpftool(8).
    
    Assign names starting with 'sd_' prefix:
    * firewall program names are 'sd_fw_ingress' for ingress attach
    point and 'sd_fw_egress' for egress.
    * 'sd_devices' for devices prog
    
    'sd_' prefix is already used in source-compiled programs, e.g.
    sd_restrictif_i, sd_restrictif_e, sd_bind6.
    
    The name must not be longer than 15 characters or BPF_OBJ_NAME_LEN - 1.
    
    Assign names only to programs loaded to kernel by systemd since
    programs pinned to bpffs are already loaded.