FT: Discard EAPOL-Start frames when FT was used for association

FT: Discard EAPOL-Start frames when FT was used for association

When FT is used, reauthentication to generate a new PMK-R0 would be
complicated since the current AP might not be the one with which the
currently used PMK-R0 was generated. IEEE Std 802.11-2020, 13.4.2 (FT
initial mobility domain association in an RSN) mandates STA to perform a
new FT initial mobility domain association whenever its Supplicant would
trigger sending of an EAPOL-Start frame.

Discard received EAPOL-Start frames from STAs that use FT to avoid
unexpected behavior. This is important in particular if a driver were to
allow unprotected EAPOL-Start frames to be processed when TK has been
configured.

Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>