ssl-opt.sh: Fix list of TLS 1.2 key exchanges with cert

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 996cd1a..e2f9206 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -251,7 +251,7 @@
     fi
 }
 
-TLS1_2_KEY_EXCHANGES_WITH_CERT="MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED \
+TLS1_2_KEY_EXCHANGES_WITH_CERT="MBEDTLS_KEY_EXCHANGE_RSA_ENABLED \
                                 MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED \
                                 MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED \
                                 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED \