imx8mn_ddr4_evk: Allow booting the kernel by default Currently it is not possible to boot Linux from the SD card by default. Make the necessary adjustments to allow it. Reported-by: Peter Bergin <peter@berginkonsult.se> Signed-off-by: Fabio Estevam <festevam@gmail.com> Tested-by: Andrey Zhizhikin <andrey.z@gmail.com> # imx8mn_ddr4_evk Reviewed-by: Peng Fan <peng.fan@nxp.com>