It was wrongly assumed that part.size is meagured in Mb. In fact it's
in Kb, so there is no need to convert bitbake variable ROOTFS_SIZE as
it's also in Kb.
(From OE-Core rev: 3703ecb4aa5267e6d7330e7978cc7c3bb2250ead)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>