Merge branch 'PR/losetup-remove' of https://github.com/karelzak/util-linux-work

Merge branch 'PR/losetup-remove' of https://github.com/karelzak/util-linux-work

* 'PR/losetup-remove' of https://github.com/karelzak/util-linux-work:
  losetup: improve command line option processing
  lostup: report EACCES on loop-control
  losetup: improve --remove documentation
  losetup: make --remove a long-only option with mutual exclusivity
  lib/loopdev: introduce loopcxt_get_device_nr() helper
  losetup: add error feedback for --remove command