Avoid theoretical NULL pointer dereference from debug code

Avoid theoretical NULL pointer dereference from debug code

The change to use wpa_dbg() in wpa_sm_parse_own_wpa_ie() could result
in a NULL pointer dereference if the function were called when WPA
state machine has not been initialized. While this cannot really
happen in practice, it is better to be prepared for that since that
was the case before the wpa_dbg() change.