OpenSSL: Simplify EAP-FAST peer workaround

OpenSSL: Simplify EAP-FAST peer workaround

Commit d4913c585ec9b62a667473878a7fd7d8600d3388 ('OpenSSL: Fix EAP-FAST
peer regression') introduced a workaround to use a new SSL_CTX instance
set for TLSv1_method() when using EAP-FAST. While that works, it is
unnecessarily complex since there is not really a need to use a separate
SSL_CTX to be able to do that. Instead, simply use SSL_set_ssl_method()
to update the ssl_method for the SSL instance. In practice, this commit
reverts most of the tls_openssl.c changes from that earlier commit and
adds that single call into tls_connection_set_params() based on EAP-FAST
flag.

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