imx: support i.MX8QM MEK board

Add i.MX8QM MEK board support.
Included a basic dts, enabled SPL FIT

Boot log as below:
U-Boot SPL 2019.01-rc1-00029-gf002213219 (Dec 24 2018 - 10:28:30 +0800)
Normal Boot
Trying to boot from MMC2_2

U-Boot 2019.01-rc1-00029-gf002213219 (Dec 24 2018 - 10:28:30 +0800)

CPU:   NXP i.MX8QM RevB A53 at 142933 MHz

Model: Freescale i.MX8QM MEK
Board: iMX8QM MEK
Build: SCFW 9330215b
Boot:  SD1
DRAM:  6 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... *** Warning - bad CRC, using default environment

In:    serial@5a060000
Out:   serial@5a060000
Err:   serial@5a060000
Net:
Error: ethernet@5b040000 address not set.
eth-1: ethernet@5b040000
Hit any key to stop autoboot:  0

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/dts/fsl-imx8qm-mek-u-boot.dtsi b/arch/arm/dts/fsl-imx8qm-mek-u-boot.dtsi
new file mode 100644
index 0000000..5d50eb0
--- /dev/null
+++ b/arch/arm/dts/fsl-imx8qm-mek-u-boot.dtsi
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 NXP
+ */
+
+&mu {
+	u-boot,dm-spl;
+};
+
+&clk {
+	u-boot,dm-spl;
+};
+
+&iomuxc {
+	u-boot,dm-spl;
+};
+
+&pd_lsio {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio0 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio1 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio2 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio3 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio4 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio5 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio6 {
+	u-boot,dm-spl;
+};
+
+&pd_lsio_gpio7 {
+	u-boot,dm-spl;
+};
+
+&pd_conn {
+	u-boot,dm-spl;
+};
+
+&pd_conn_sdch0 {
+	u-boot,dm-spl;
+};
+
+&pd_conn_sdch1 {
+	u-boot,dm-spl;
+};
+
+&pd_conn_sdch2 {
+	u-boot,dm-spl;
+};
+
+&gpio0 {
+	u-boot,dm-spl;
+};
+
+&gpio1 {
+	u-boot,dm-spl;
+};
+
+&gpio2 {
+	u-boot,dm-spl;
+};
+
+&gpio3 {
+	u-boot,dm-spl;
+};
+
+&gpio4 {
+	u-boot,dm-spl;
+};
+
+&gpio5 {
+	u-boot,dm-spl;
+};
+
+&gpio6 {
+	u-boot,dm-spl;
+};
+
+&gpio7 {
+	u-boot,dm-spl;
+};
+
+&lpuart0 {
+	u-boot,dm-spl;
+};
+
+&usdhc1 {
+	u-boot,dm-spl;
+};
+
+&usdhc2 {
+	u-boot,dm-spl;
+};