imx: imx8mq_evk: convert to OF_UPSTREAM

Convert i.MX8MQ EVK to OF_UPSTREAM

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/imx8mq_evk_defconfig b/configs/imx8mq_evk_defconfig
index 941b845..3a2d88a 100644
--- a/configs/imx8mq_evk_defconfig
+++ b/configs/imx8mq_evk_defconfig
@@ -11,7 +11,7 @@
 CONFIG_SYS_I2C_MXC_I2C2=y
 CONFIG_SYS_I2C_MXC_I2C3=y
 CONFIG_DM_GPIO=y
-CONFIG_DEFAULT_DEVICE_TREE="imx8mq-evk"
+CONFIG_DEFAULT_DEVICE_TREE="freescale/imx8mq-evk"
 CONFIG_SPL_TEXT_BASE=0x7E1000
 CONFIG_TARGET_IMX8MQ_EVK=y
 CONFIG_DM_RESET=y