cgroup: Check for ret during cgroup1_base_files cft addition

There is no check for possible failure while populating
cgroup1_base_files cft in css_populate_dir(), like its cgroup v2 counter
parts cgroup_{base,psi}_files.  In case of failure, the cgroup might not
be set up right.  Add ret value check to return on failure.
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup/cgroup.c

@@ -1731,8 +1731,10 @@ static int css_populate_dir(struct cgroup_subsys_state *css)
 					return ret;
 			}
 		} else {
-			cgroup_addrm_files(css, cgrp,
-					   cgroup1_base_files, true);
+			ret = cgroup_addrm_files(css, cgrp,
+						 cgroup1_base_files, true);
+			if (ret < 0)
+				return ret;
 		}
 	} else {
 		list_for_each_entry(cfts, &css->ss->cfts, node) {