libnvdimm, namespace: lift single pmem limit in scan_labels()

Now that the rest of the infrastructure has been converted to handle
multi-pmem configurations, lift the artificial barrier at scan time.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/namespace_devs.c

@@ -2070,9 +2070,6 @@ static struct device **scan_labels(struct nd_region *nd_region)
 				}
 			} else
 				devs[count++] = dev;
-
-			/* we only expect one valid pmem label set per region */
-			break;
 		}
 	}