Pull libnvdimm and device-dax updates from Dan Williams:

 - Fix the error code polarity for the device-dax/mapping attribute

 - For the device-dax and libnvdimm bus implementations stop
   implementing a useless return code for the remove() callback.

 - Miscellaneous cleanups

* tag 'libnvdimm-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax-device: Make remove callback return void
  device-dax: Drop an empty .remove callback
  device-dax: Fix error path in dax_driver_register
  device-dax: Properly handle drivers without remove callback
  device-dax: Prevent registering drivers without probe callback
  libnvdimm: Make remove callback return void
  libnvdimm/dimm: Simplify nvdimm_remove()
  device-dax: Fix default return code of range_parse()