CONFIG_DEVICE_TREE was the only user of CONFIG_WANT_DEVICE_TREE but
it was removed in commit id 25431333
(bootwrapper: Build multiple cuImages).

This removes CONFIG_WANT_DEVICE_TREE from Kconfig and the defconfigs.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

512x is very similar to 83xx and most
of this is patterned after code from 83xx.

New platform:
    changed:
	arch/powerpc/Kconfig
	arch/powerpc/platforms/Kconfig
	arch/powerpc/platforms/Kconfig.cputype
	arch/powerpc/platforms/Makefile
    new:
	arch/powerpc/platforms/512x/*
	include/asm-powerpc/mpc512x.h
Signed-off-by: NJohn Rigby <jrigby@freescale.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>