ARM: imx: Switch Data Modul i.MX8M Mini eDM SBC to USB251x Hub driver

Replace the ad-hoc I2C register programming scripted in board
environment with U-Boot DM driver.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>