cros_make_image_bootable: remove rootfs_hash_pad argument

The argument `rootfs_hash_pad` is unused in this script.

Rely on CQ to catch any critical callers expecting to be able to use it.

BUG=None
TEST=CQ

Change-Id: Id6aba991e3f0d8020d8ab03db7484888b80a698a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/4545942
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Jeffery Miller <jefferymiller@google.com>
Tested-by: Jeffery Miller <jefferymiller@google.com>
1 file changed