busybox: add missing kconfig symbol type for BUSYBOX_USE_LIBRPC

SVN-Revision: 26437

package/busybox/Config.in

@@ -20,6 +20,7 @@ config BUSYBOX_CONFIG_HUSH
 	default n if !NOMMU
 
 config BUSYBOX_USE_LIBRPC
+	bool
 	depends USE_UCLIBC
 	default y if BUSYBOX_CONFIG_FEATURE_HAVE_RPC