Rename MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL to MBEDTLS_SSL_PROTO_TLS1_3

As we have now a minimal viable implementation of TLS 1.3,
let's remove EXPERIMENTAL from the config option enabling
it.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/scripts/generate_tls13_compat_tests.py b/tests/scripts/generate_tls13_compat_tests.py
index 4a4f8fa..a6d2fe7 100755
--- a/tests/scripts/generate_tls13_compat_tests.py
+++ b/tests/scripts/generate_tls13_compat_tests.py
@@ -278,7 +278,7 @@
     def pre_checks(self):
         ret = ['requires_config_enabled MBEDTLS_DEBUG_C',
                'requires_config_enabled MBEDTLS_SSL_CLI_C',
-               'requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL',
+               'requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3',
                'requires_config_disabled MBEDTLS_USE_PSA_CRYPTO']
 
         if self._compat_mode: