vboot_reference: fix pointer issue in vmlinuz recontruction

vmlinuz_header_address was using an offset as opposed to a pointer.

BUG=None
BRANCH=None
TEST=Take a kernel block and reconstruction the vmlinuz image:
     "vbutil_kernel --get-vmlinuz kern0 --vmlinuz-out vm.out"
     Then, try to kexec vm.out.

Change-Id: Ifb41a00fd73f3222673467eef370c7abdbd0fd9c
Reviewed-on: https://chromium-review.googlesource.com/245441
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Commit-Queue: Shelley Chen <shchen@chromium.org>
Tested-by: Shelley Chen <shchen@chromium.org>
1 file changed