linux-imx

soc: imx8: Use existing of_root directly

There is common of_root for reference, no need to find it
from DT again, use of_root directly to make driver simple.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>