lib/fit: support booting initrd placed above 4GiB

Store initrd offset as 64bit integer.

Tested on Cavium CN81XX EVB: The initrd could be loaded when placed
above 4GiB. Previously it failed to find the initrd.

Change-Id: I5d1ae860ae4a4465546bc0ef89937d611d1e56ab
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/28002
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
3 files changed