nvdimm: Fix return value of nvdimm_bus_init() if class_create() fails

Return proper error if class_create() fails.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 73442bd..7e2c43f 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -699,8 +699,10 @@
 	nvdimm_major = rc;
 
 	nd_class = class_create(THIS_MODULE, "nd");
-	if (IS_ERR(nd_class))
+	if (IS_ERR(nd_class)) {
+		rc = PTR_ERR(nd_class);
 		goto err_class;
+	}
 
 	return 0;