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/sysv.c b/util-linux/volume_id/sysv.c
index 7cc1d21..7b4b536 100644
--- a/util-linux/volume_id/sysv.c
+++ b/util-linux/volume_id/sysv.c
@@ -20,6 +20,15 @@
 
 //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_SYSV) += sysv.o
 
+//config:
+//config:config FEATURE_VOLUMEID_SYSV
+//config:	bool "sysv filesystem"
+//config:	default y
+//config:	depends on VOLUMEID
+//config:	help
+//config:	  TODO
+//config:
+
 #include "volume_id_internal.h"
 
 #define SYSV_NICINOD			100