The new variable allows for images to be created without an
editable boot line in syslinux. Default behavior remains unchanged.
(From OE-Core rev: 935578c139a260c18e437419be82d7fd7e8be81a)
Signed-off-by: Michael Davis <michael.davis@essvote.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>