feat(intel): add build config and variant for N5X

Add build config and variant for Intel N5X platforms.

Signed-off-by: Sieu Mun Tang <sieu.mun.tang@intel.com>
Change-Id: I44c7d8f50244e79bb3f5773157fbef0f892a2c85
diff --git a/group/tf-l1-build-plat/n5x-default:nil b/group/tf-l1-build-plat/n5x-default:nil
new file mode 100644
index 0000000..75f5f1d
--- /dev/null
+++ b/group/tf-l1-build-plat/n5x-default:nil
@@ -0,0 +1,5 @@
+#
+# Copyright (c) 2020-2022 Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#