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/suites/test_suite_mps.function b/tests/suites/test_suite_mps.function
index 9df8a3c..c40c50e 100644
--- a/tests/suites/test_suite_mps.function
+++ b/tests/suites/test_suite_mps.function
@@ -20,7 +20,7 @@
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
- * depends_on:MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+ * depends_on:MBEDTLS_SSL_PROTO_TLS1_3
  * END_DEPENDENCIES
  */