imx: imx8m[m/p]_phycore: Enable DM_SERIAL

Enable CONFIG_DM_SERIAL. uart and its pinmux was already
marked with u-boot,dm-spl.
Move preloader_console_init after spl_early_init to make sure driver
model work.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Tested-by: Teresa Remmet <t.remmet@phytec.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
6 files changed