This list includes block devices of:
* Boot medium [archisodevice] (only if no copytoram= is used)
* Loop medium [img_dev] (only if no copytoram= is used)
* COW space [cowdevice] (only if cowdevice= is used (no tmpfs is used))
* Loop devices used for SquashFS images.
* Loop devices used for device-mapper devices (two per each dm-device, one RO{*.fs} and one RW{*.cow})

Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>