ARM: mvebu: a38x: Add missing SPDX license identfier

[u-boot] / drivers / ddr / marvell / a38x / mv_ddr_build_message.c

// SPDX-License-Identifier: GPL-2.0
const char mv_ddr_build_message[] = "";
const char mv_ddr_version_string[] = "mv_ddr: mv_ddr-armada-17.10.4";