WPS: Add support for NCF password token from AP

WPS: Add support for NCF password token from AP

The new hostapd ctrl_iface command WPS_NFC_TOKEN can now be used to
manage AP-as-Enrollee operations with NFC password token. WPS/NDEF
parameters to this command can be used to generate a new NFC password
token. enable/disable parameters can be used to enable/disable use of
NFC password token (instead of AP PIN) for external Registrars.

A preconfigured NFS password token can be used by providing its
parameters with new hostapd.conf fields wps_nfc_dev_pw_id,
wps_nfc_dh_pubkey, wps_nfc_dh_privkey, and wps_nfc_dev_pw. This use
will also depend on WPS_NFC_TOKEN enable/disable commands, i.e., the
configured NFS password token is disabled by default.

Signed-hostap: Jouni Malinen <j@w1.fi>