tqma6q_mba6: Convert to watchdog driver model

Commit 68dcbdd594d4 ("ARM: imx: Add weak default reset_cpu()") caused
the 'reset' command in U-Boot to not cause a board reset.

Fix it by switching to the watchdog driver model via sysreset, which
is the preferred method for implementing the watchdog reset.

Signed-off-by: Fabio Estevam <festevam@denx.de>
diff --git a/arch/arm/dts/imx6qdl-mba6-u-boot.dtsi b/arch/arm/dts/imx6qdl-mba6-u-boot.dtsi
new file mode 100644
index 0000000..78457ef
--- /dev/null
+++ b/arch/arm/dts/imx6qdl-mba6-u-boot.dtsi
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "imx6qdl-u-boot.dtsi"
+
+/ {
+	wdt-reboot {
+		compatible = "wdt-reboot";
+		wdt = <&wdog1>;
+		bootph-pre-ram;
+	};
+};
+
+&wdog1 {
+	bootph-pre-ram;
+};