Linux expects that the /dev/console node is present in
the rootfs image. Create the node in rootfs images, in
order to make std{in,out,err} usable even in early init
process.

Note: tar.gz and cpio.gz images are not handled yet.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37847 3c298f89-4303-0410-b956-a3cf2f4a3e73