wic: Using the right rootfs size during prepare_rootfs
The commit
8e48b4d6c4 makes wic ignores IMAGE_ROOTFS_SIZE for rootfs
size and makes it uses the computed one only. Re-add support for
IMAGE_ROOTFS_SIZE variable and compute roots size only if the former
is not defined. Moreover the size of a provided directory with
--rootfs-dir="" in the .wks file should always be computed on the fly,
else every partition will be constrained to be the same size as what
ever value was in ROOTFS_SIZE.
Signed-off-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
