The ubdev01 profile defines its own MTDPARTS with smaller firmware
partition, so give it its own UBNT_BOARD in mkfwimage.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Backport of r48828
git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@48847 3c298f89-4303-0410-b956-a3cf2f4a3e73