hostapd: add wpa_disable_eapol_key_retries option

hostapd: add wpa_disable_eapol_key_retries option

Commit b6c3931ad6554357a108127797c8d7097a93f18f introduced an AP-side
workaround for key reinstallation attacks. This option can be used to
mitigate KRACK on the station side, in case those stations cannot be
updated. Since many devices are out there will not receive an update
anytime soon (if at all), it makes sense to include this workaround.

Unfortunately this can cause interoperability issues and reduced
robustness of key negotiation, so disable the workaround by default, and
add an option to allow the user to enable it if he deems necessary.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
(cherry picked from commit c5f97c9372da3229350184fb263c97d9ea8944c5)