imx: mx6sllevk: select DM_SERIAL

Select DM_SERIAL

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/dts/imx6sll-evk-u-boot.dtsi b/arch/arm/dts/imx6sll-evk-u-boot.dtsi
new file mode 100644
index 0000000..14d0b58
--- /dev/null
+++ b/arch/arm/dts/imx6sll-evk-u-boot.dtsi
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019, 2021 NXP
+ */
+
+&pinctrl_uart1 {
+	u-boot,dm-pre-reloc;
+};