armv8: dts: fsl: Remove cpu nodes from Layerscape DTSIs

Currently layescape SoCs are not using cpu nodes. So removing
them in favour of compatibly with  similar SoCs that
have different cores like LS2080A and LS2088A.

This has been tested on LS2080AQDS, LS1043ARDB, LS1012ARDB.

Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Signed-off-by: Abhimanyu Saini <abhimanyu.saini@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>