libnvdimm: IS_ERR() usage cleanup

Prompted by commit 287980e4 "remove lots of IS_ERR_VALUE abuses", I
ran make coccicheck against drivers/nvdimm/ and found that:

	if (IS_ERR(x))
		return PTR_ERR(x);
	return 0;

...can be replaced with PTR_ERR_OR_ZERO().
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/bus.c

@@ -395,12 +395,10 @@ int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
 	dev = device_create(nd_class, &nvdimm_bus->dev, devt, nvdimm_bus,
 			"ndctl%d", nvdimm_bus->id);
 
-	if (IS_ERR(dev)) {
+	if (IS_ERR(dev))
 		dev_dbg(&nvdimm_bus->dev, "failed to register ndctl%d: %ld\n",
 				nvdimm_bus->id, PTR_ERR(dev));
-		return PTR_ERR(dev);
-	}
-	return 0;
+	return PTR_ERR_OR_ZERO(dev);
 }
 
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus)

drivers/nvdimm/claim.c

@@ -266,9 +266,8 @@ int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
 
 	nsio->addr = devm_memremap(dev, res->start, resource_size(res),
 			ARCH_MEMREMAP_PMEM);
-	if (IS_ERR(nsio->addr))
-		return PTR_ERR(nsio->addr);
-	return 0;
+
+	return PTR_ERR_OR_ZERO(nsio->addr);
 }
 EXPORT_SYMBOL_GPL(devm_nsio_enable);