tls13: srv: Fix MBEDTLS_SSL_SESSION_TICKETS guard position

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 3b7fc83..d0e8195 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -608,18 +608,16 @@
                     ssl, ciphersuites, ciphersuites_end,
                     &cipher_suite, &ciphersuite_info);
                 break;
-            case MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION:
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
+            case MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION:
                 ret = ssl_tls13_select_ciphersuite_for_resumption(
                     ssl, ciphersuites, ciphersuites_end, &session,
                     &cipher_suite, &ciphersuite_info);
                 if (ret != 0) {
                     mbedtls_ssl_session_free(&session);
                 }
-#else
-                ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
-#endif
                 break;
+#endif
             default:
                 return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
         }