fsl-lsch2: csu: remove multiple calling function

Function enable_layerscape_ns_access() is alreayd called soc-wide.
Remove duplicated calling from individual boards.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
[YS: Add commit message]
Reviewed-by: York Sun <york.sun@nxp.com>