pack.py: Updated section name to reflect 'lkboot'

Updated section name to 'lkboot' that will be
used to display while flashing the image.

Change-Id: I38e66f03963bc008bdee3036e980fb4c6b930ec0
Signed-off-by: Gokul Sriram Palanisamy <gokulsri@codeaurora.org>
1 file changed