libnvdimm: Remove unused nd_attach_ndns

nd_attach_ndns() hasn't been used since 2017's
commit 452bae0aede7 ("libnvdimm: fix nvdimm_bus_lock() vs device_lock()
ordering")

Remove it.

Note the __ version is still used and has been left.

Signed-off-by: Dr. David Alan Gilbert <[e-mail]>
Reviewed-by: Ira Weiny <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Ira Weiny <[e-mail]>

drivers/nvdimm/claim.c

···
 	return true;
 }
 
-bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
-		struct nd_namespace_common **_ndns)
-{
-	bool claimed;
-
-	nvdimm_bus_lock(&attach->dev);
-	claimed = __nd_attach_ndns(dev, attach, _ndns);
-	nvdimm_bus_unlock(&attach->dev);
-	return claimed;
-}
-
 static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
 {
 	struct nd_region *nd_region = to_nd_region(dev->parent);

drivers/nvdimm/nd-core.h

···
 resource_size_t __nvdimm_namespace_capacity(struct nd_namespace_common *ndns);
 void nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
-bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
-		struct nd_namespace_common **_ndns);
 bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
 		struct nd_namespace_common **_ndns);
 ssize_t nd_namespace_store(struct device *dev,