armv8/fsl-layerscape: fdt: Remove offline cores from cooling device maps

armv8/fsl-layerscape: fdt: Remove offline cores from cooling device maps

Some processor families use a generic device tree, and rely on u-boot
fixups to massage that for lower core count personalities (i.e. NXP
LX2* family). For example, the LX2160A device tree will be used and
then modified to offline non-existent cores when running on an 8-core
LX2080A.

However, the cooling maps still contain references to the non-existent
core phandles, resulting in:

    OF: /thermal-zones/cluster6-7-thermal/cooling-maps/map0:
        could not find phandle 15

Rebuild the cooling maps as non-existent cores are deleted.

Signed-off-by: Anthony Pighin <anthony.pighin@nokia.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>