spb-rs2/ipv4: show protocols all mline

mline BGP --- start 2020-01-20 Passive

Description:    mline/48558/AS48558
  BGP state:          Passive
    Neighbor address: 185.1.152.240
    Neighbor AS:      48558
    Local AS:         50817
  Channel ipv4
    State:          DOWN
    Table:          rib4
    Preference:     100
    Input filter:   (unnamed)
    Output filter:  (unnamed)
    Import limit:   5000
      Action:       disable