DPP: Use wildcard BSSID in GAS query frames

DPP: Use wildcard BSSID in GAS query frames

Force use of the wildcard BSSID address in GAS query frames with DPP
regardless of how the gas_address3 configuration parameter is set. DPP
specification mandates this and the use of GAS here is really outside
the context of a BSS, so using the wildcard BSSID makes sense even for
the corner case of Configurator running on a known AP (where IEEE 802.11
standard would allow the BSSID of the AP to be used).

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>