WPS: Add new mechanism for NFC config method using password token

WPS: Add new mechanism for NFC config method using password token

Instead of requiring low-level access to an NFC device and synchronous
operations, the new WPS_NFC_TOKEN and WPS_NFC ctrl_iface commands can be
used to build a NFC password token and initiate WPS protocol run using
that token (or pre-configured values) as separate commands. The
WPS_NFC_TOKEN output can be written to a NFC tag using an external
program, i.e., wpa_supplicant does not need to have low-level code for
NFC operations for this.

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