dissect: simplify flags for recurse_dir()

dissect: simplify flags for recurse_dir()

We are not interested in the struct dirent data, hence there's no point
in passing RECURSE_DIR_ENSURE_TYPE. Let's drop it, and thus avoid some
extrac work on file systems where readdir() does not report .d_type.

Also drop RECURSE_DIR_SAME_MOUNT, because DDIs after all may contain
multiple partitions, and we mount them all together. The --list command
really should report the full set of files in an image.