Add a wrapper function to retrieve the FDT size from the FDT header. This
is primarily to avoid libfdt include paths for the whole kernel.
Signed-off-by: NRob Herring <robh@kernel.org>
Tested-by: NGrant Likely <grant.likely@linaro.org>
Tested-by: NStephen Chivers <schivers@csc.com>