volume_id: Adopt to new kbuild style.

Kbuild instructions for util-linux/volume_id are moved into the
source files according to the new build 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/unused_highpoint.c b/util-linux/volume_id/unused_highpoint.c
index 17b7b32..990875c 100644
--- a/util-linux/volume_id/unused_highpoint.c
+++ b/util-linux/volume_id/unused_highpoint.c
@@ -18,6 +18,8 @@
  *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+//kbuild:### lib-$(CONFIG_FEATURE_VOLUMEID_HIGHPOINTRAID) += highpoint.o
+
 #include "volume_id_internal.h"
 
 struct hpt37x_meta {