imx: imx8mq_evk: Enable dynamic settings to mmcdev and mmcroot

Enable dynamic settings to mmcdev and mmcroot for i.MX8MQ-EVK
Since we are here, clean up the including headers

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/freescale/imx8mq_evk/imx8mq_evk.c b/board/freescale/imx8mq_evk/imx8mq_evk.c
index f833996..18e83d9 100644
--- a/board/freescale/imx8mq_evk/imx8mq_evk.c
+++ b/board/freescale/imx8mq_evk/imx8mq_evk.c
@@ -50,6 +50,10 @@
 
 int board_late_init(void)
 {
+#if CONFIG_IS_ENABLED(ENV_IS_IN_MMC)
+	board_late_mmc_env_init();
+#endif
+
 #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 	env_set("board_name", "EVK");
 	env_set("board_rev", "iMX8MQ");