rename ticket_flags helper functions to generic ones

Ticket flags is quite generic and may make sense in the
future versions of TLS or even in TLS 1.2 with new
extensions. This change remane the ticket_flags helper
functions with more generic `mbedtls_ssl_session` prefix
instead of `mbedtls_ssl_tls13_session`.

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index d5dbf82..654a7da 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -170,10 +170,12 @@
      * We regard the ticket with incompatible key exchange modes as not match.
      */
     ret = MBEDTLS_ERR_SSL_TICKET_INVALID_KEX_MODE;
-    MBEDTLS_SSL_DEBUG_TICKET_FLAGS(4, session->ticket_flags);
+    MBEDTLS_SSL_DEBUG_TICKET_FLAGS(4,
+                                   session->ticket_flags);
     if (mbedtls_ssl_tls13_check_kex_modes(ssl,
-                                          mbedtls_ssl_tls13_session_get_ticket_flags(
-                                              session, MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL))) {
+                                          mbedtls_ssl_session_get_ticket_flags(
+                                              session,
+                                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL))) {
         MBEDTLS_SSL_DEBUG_MSG(3, ("No suitable key exchange mode"));
         goto exit;
     }
@@ -2632,10 +2634,10 @@
 #endif
 
     /* Set ticket_flags depends on the advertised psk key exchange mode */
-    mbedtls_ssl_tls13_session_clear_ticket_flags(
+    mbedtls_ssl_session_clear_ticket_flags(
         session, MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK);
 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
-    mbedtls_ssl_tls13_session_set_ticket_flags(
+    mbedtls_ssl_session_set_ticket_flags(
         session, ssl->handshake->tls13_kex_modes);
 #endif
     MBEDTLS_SSL_DEBUG_TICKET_FLAGS(4, session->ticket_flags);