libnvdimm/region: Rewrite _probe_success() to _advance_seeds()

libnvdimm/region: Rewrite _probe_success() to _advance_seeds()

The nd_region_probe_success() helper collides seed management with
nvdimm->busy tracking. Given the 'busy' increment is handled internal to the
nd_region driver 'probe' path move the decrement to the 'remove' path.
With that cleanup the routine can be renamed to the more descriptive
nd_region_advance_seeds().

The change is prompted by an incoming need to optionally advance the
seeds on other events besides 'probe' success.

Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/20190905154603.10349-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>