update_kernel: Allow you to specify the "root offset"

If you're using a nonstandard kernel partition you'll probably want to
modify where the root partition is relative to it.  Ideally
update_kernel could do this automatically, but since this script is
officially deprecated (see http://crosreview.com/203165) we'll just
add a flag.

BUG=None
TEST=update_kernel.sh --partition=/dev/mmcblk0p4 --rootoff=-1 \
  --remote=${HOST} --bootonce

Change-Id: I2a3d1abe4fca92ccaaa7d32730866dc51da723da
Reviewed-on: https://chromium-review.googlesource.com/207166
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>
Commit-Queue: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
1 file changed