nixos/filesystems: skip fsck for bind mounts

Without this change, configurations like
```nix
fileSystems."/path/to/bindMountedDirectory" = {
  device = "/path/to/originalDirectory";
  options = [ "bind" ];
};
```
will lead to a warning message in `dmesg`:
```
systemd-fstab-generator: Checking was requested for "/path/to/originalDirectory", but it is not a device.
```
This happens because the generated /etc/fstab entry contains a non-zero fsck pass number, which doesn't make sense for a bind mount.

0 files changed, 0 insertions, 0 deletions