interface for nfc handover supplicant commands

expose:
  NFC_GET_HANDOVER_SEL
  NFC_GET_HANDOVER_REQ
  NFC_REPORT_HANDOVER

These are used in for setting up WFD with NFC and
are only accessible given the CONNECTIVITY_INTERNAL
permission.

Change-Id: Ia43afc137d474822cad896d335530654081a808c