qcacld-3.0: Fix PMF regression for SAP
In PMF SAP case iface->rmfEnabled is not set and thus even
unprotected frames are received by driver and processed.
To fix this set iface->rmfEnabled while adding station.
Change-Id: I3cbe5d7d64ee0d38f64f9cf256ce338163edd302
CRs-Fixed: 2048364