Add an option allow canned EAP-Success for wired IEEE 802.1X

Add an option allow canned EAP-Success for wired IEEE 802.1X

For wired IEEE 802.1X authentication, phase1="allow_canned_success=1"
can now be used to configure a mode that allows EAP-Success (and
EAP-Failure) without going through authentication step. Some switches
use such sequence when forcing the port to be authorized/unauthorized or
as a fallback option if the authentication server is unreachable. By
default, wpa_supplicant discards such frames to protect against
potential attacks by rogue devices, but this option can be used to
disable that protection for cases where the server/authenticator does
not need to be authenticated.

When enabled, this mode allows EAP-Success/EAP-Failure as an immediate
response to EAPOL-Start (or even without EAPOL-Start) and EAP-Success is
also allowed immediately after EAP-Identity exchange (fallback case for
authenticator not being able to connect to authentication server).

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