Better handling of multi-flash-device KDZ files

[ehem]

On newer LG devices instead of the on-board flash being presented as /dev/block/mmcblk0p[0-9]+, you get /dev/block/sd[a-g][0-9]+ kdztools was designed for only a single on-board flash device and the current code has a very hackish implementation of multiple major devices. This needs to be fixed.