volume_id: Adopt to new config style.

Config instructions for util-linux/volume_id are moved into the
source files according to the new config feature.

No code change.

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/volume_id/nilfs.c b/util-linux/volume_id/nilfs.c
index daa0294..934856f 100644
--- a/util-linux/volume_id/nilfs.c
+++ b/util-linux/volume_id/nilfs.c
@@ -21,6 +21,15 @@
 
 //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_NILFS) += nilfs.o
 
+//config:
+//config:config FEATURE_VOLUMEID_NILFS
+//config:	bool "nilfs filesystem"
+//config:	default y
+//config:	depends on VOLUMEID
+//config:	help
+//config:	  TODO
+//config:
+
 #include "volume_id_internal.h"
 
 #define NILFS_UUID_SIZE 16