the old rx_lost_o indicates as before two "problems"
1. one or more frames have been lost
2. one or more blocks inside the frame have been lost (probably because
   of CRC error)
However, now we have 3 more outputs:
rx_lost_blocks_o     - indicates only losses of block(s)
rx_lost_frames_o     - indicates only losses of frame(s)
rx_lost_frames_cnt_o - when rx_lost_frames_o=HIGH, indicates how many
                       frames have been lost