WPS: Add support for AP reconfiguration with wps_reg

WPS: Add support for AP reconfiguration with wps_reg

wpa_supplicant can now reconfigure the AP by acting as an External
Registrar with the wps_reg command. Previously, this was only used
to fetch the current AP settings, but now the wps_reg command has
optional arguments which can be used to provide the new AP
configuration. When the new parameters are set, the WPS protocol run
is allowed to continue through M8 to reconfigure the AP instead of
stopping at M7.