wlan: Save RSN auth type for RSN association

Save RSN auth type in related context for RSN assocoation.
Some OWE specific operation need to be done according to
this RSN auth type since we cannot tell if a STA / SAP is OWE,
WPA2 or OPEN by its auth type OPEN.

Change-Id: I17dd72c7adf1c663725ac58ce263f4408d9c967b
CRs-Fixed: 2734691