Convert all util-linux/* applets to "new style" applet definitions

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

util-linux/rdev.c

@@ -8,6 +8,15 @@
  * Licensed under GPLv2, see file LICENSE in this source tree.
  *
  */
+//config:config RDEV
+//config:	bool "rdev"
+//config:	default y
+//config:	help
+//config:	  Print the device node associated with the filesystem mounted at '/'.
+
+//applet:IF_RDEV(APPLET(rdev, BB_DIR_USR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_RDEV) += rdev.o
 
 //usage:#define rdev_trivial_usage
 //usage:       ""