of/fdt: add FDT address translation support

Copy u-boot's FDT address translation code from common/fdt_support. This
code was originally based on the kernel's unflattened DT address parsing
code.

This commit can be reverted once relicensing of this code to GPLv2/BSD
is done and it is added to libfdt.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Grant Likely <grant.likely@linaro.org>