imx: imx8mm_evk: Enable dynamic settings to mmcdev and mmcroot

Enable dynamic settings to mmcdev and mmcroot for i.MX8MM-EVK

Signed-off-by: Peng Fan <peng.fan@nxp.com>

board/freescale/imx8mm_evk/imx8mm_evk.c

@@ -59,6 +59,9 @@ int board_mmc_get_env_dev(int devno)
 
 int board_late_init(void)
 {
+	if (IS_ENABLED(CONFIG_ENV_IS_IN_MMC))
+		board_late_mmc_env_init();
+
 	if (IS_ENABLED(CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG)) {
 		env_set("board_name", "EVK");
 		env_set("board_rev", "iMX8MM");