Fix some issues with displaying Ethernet media status on recent FreeBSD kernels.

Fix some issues with displaying Ethernet media status on recent FreeBSD kernels.

- Don't apply IFM_SUBTYPE to the raw subtype in the description table.
  IFM_SUBTYPE() requires a fully populated word and was truncating values
  in the table when comparing resulting in false matches (notably
  "10GBase-KX4" for the no media case) after recent changes to add extended
  Ethernet media states in FreeBSD.
- Explicitly check for IFM_ETHER.
- Use SIOCGIFXMEDIA when present to obtain extended media states on newer
  kernels.
- Explicitly handle "no carrier".