arm: dts: s400: Fix status for eMMC and SDIO ports

Under U-boot, the WiFi SDIO Module should be disabled and the
eMMC modules should be enabled, so this patch adds an s400-u-boot.dtsi
include file specific for U-Boot that will be included by the build system.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>

arch/arm/dts/meson-axg-s400-u-boot.dtsi

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2017 Amlogic, Inc. All rights reserved.
+ */
+
+/* wifi module */
+&sd_emmc_b {
+	status = "disabled";
+};
+
+/* emmc storage */
+&sd_emmc_c {
+	status = "okay";
+};