Fix sending ANQP request to an unknown BSS while associated

Fix sending ANQP request to an unknown BSS while associated

While being associated, if an ANQP request is received for a different
AP that doesn't exist in the BSS list, the ANQP request will be sent on
the frequency of the AP that we are currently associated to.

In such a case, it is possible that the ANQP request would be sent on
a channel different than that of the requested AP, potentially delaying
other requests/activities.

Avoid sending the ANQP request to an AP that is not in the BSS list.

Signed-off-by: Matti Gottlieb <matti.gottlieb@intel.com>