[Merge] ~xypron/livecd-rootfs:risc_imgsize into livecd-rootfs:ubuntu/master

[Gauthier Jolly]

You can just check if there is a subarch defined and if there is then assume you are building an image for a board and then make the image bigger (and document this in the code).
-- 
https://code.launchpad.net/~xypron/livecd-rootfs/+git/livecd-rootfs/+merge/445058
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~xypron/livecd-rootfs:risc_imgsize into livecd-rootfs:ubuntu/master.