The previous attempt (r40717) to fix squashfx made the system bootable but
overlayfs remained broken.
This enables block2mtd again using the right partition number and naming
and adds MTD_ROOTFS_SPLIT option.
However onboard rootfs partition name had to be renamed to place overlay on
CF instead of onboard NAND.
Signed-off-by: Roman Yeryomin <roman@advem.lv>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41541 3c298f89-4303-0410-b956-a3cf2f4a3e73