iwlwifi: mvm: send all non-bufferable frames on the probe queue

AP interfaces now send all non-bufferable frames using the broadcast
station. Thus allow them to use the probe queue and don't warn about
it.

Fixes: eb045e6e ("iwlwifi: mvm: Avoid deferring non bufferable frames")
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>