Previously, when building core-image-minimal, the rootfs size would
default to 64M because we use '?=' in bitbake.conf and also '?=' in
core-image-minimal.bb.
The thing is, we'd like to have a default value for all images set
in bitbake.conf but still allow each image recipe to set its own default
value which could be overridden by users in local.conf.
Signed-off-by: Chen Qi <Qi.Chen@windriver.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
