powerpc/fsl: Removed reg property from 85xx/86xx soc node

Between the addition of the ecm/mcm law nodes and the fact that the
get_immrbase() has been using the range property of the SoC to determine
the base address of CCSR space we no longer need the reg property at
the soc node level.  It has been ill specified and varied between device
trees to cover either the {e,m}cm-law node, some odd subset of CCSR
space or all of CCSR space.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>