pkg/boot/kexec: use strconv.IntSize for parsing memory tables
pkg/boot/kexec: use strconv.IntSize for parsing memory tables

Signed-off-by: Ronald G. Minnich <f569d0af9a3481c4007b95c7180d6c41009f2513@gmail.com>

u-root/u-root,u-root/u-root,u-root/u-root