Ignore Michael MIC failure reports if cipher is not TKIP

Ignore Michael MIC failure reports if cipher is not TKIP

Some stations have been reported to send EAPOL-Key Error Reports
indicating Michael MIC failures even when the cipher is not TKIP
(e.g., when the network is using only CCMP). Ignore such reports
to avoid starting TKIP countermeasures unnecessarily. This can
prevent certaint types of denial of service attacks by insiders,
but mostly this is to work around invalid station implementations.

Signed-hostap: Jouni Malinen <j@w1.fi>