tls13: Upstream various fix in prototype

- Adjust max input_max_frag_len
- Guard transform_negotiate
- Adjust function position
- update comments
- fix wrong requirements

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index eba5e3b..7723363 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3198,12 +3198,14 @@
     size_t max_len = MBEDTLS_SSL_IN_CONTENT_LEN;
     size_t read_mfl;
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
     /* Use the configured MFL for the client if we're past SERVER_HELLO_DONE */
     if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
         ssl->state >= MBEDTLS_SSL_SERVER_HELLO_DONE )
     {
         return ssl_mfl_code_to_length( ssl->conf->mfl_code );
     }
+#endif
 
     /* Check if a smaller max length was negotiated */
     if( ssl->session_out != NULL )
@@ -3215,7 +3217,7 @@
         }
     }
 
-    // During a handshake, use the value being negotiated
+    /* During a handshake, use the value being negotiated */
     if( ssl->session_negotiate != NULL )
     {
         read_mfl = ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code );
@@ -3486,6 +3488,8 @@
  *
  *      case MBEDTLS_SSL_VERSION_TLS1_2:
  *        serialized_session_tls12 data;
+ *      case MBEDTLS_SSL_MINOR_VERSION_4:
+ *        serialized_session_tls13 data;
  *
  *   };
  *
@@ -4525,7 +4529,7 @@
     /* This has been allocated by ssl_handshake_init(), called by
      * by either mbedtls_ssl_session_reset_int() or mbedtls_ssl_setup(). */
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
-	ssl->transform = ssl->transform_negotiate;
+    ssl->transform = ssl->transform_negotiate;
     ssl->transform_in = ssl->transform;
     ssl->transform_out = ssl->transform;
     ssl->transform_negotiate = NULL;