Currently, the imx8mp_evk uses the non-DM code to initialize the PMIC. Convert to DM_PMIC, which is the recommended way to access the PMIC. While at it, fix multi-line comments style. Signed-off-by: Fabio Estevam <festevam@denx.de> Reviewed-by: Peng Fan <peng.fan@nxp.com>