package/iputils: fix IDN support

iputils depends on libidn2 since version s20180629 and
https://github.com/iputils/iputils/commit/665fe4d30ff8b6649454ae25e4768b2f23605332

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/iputils/iputils.mk

@@ -24,9 +24,9 @@ else
 IPUTILS_CONF_OPTS += -DUSE_CAP=false
 endif
 
-ifeq ($(BR2_PACKAGE_LIBIDN),y)
+ifeq ($(BR2_PACKAGE_LIBIDN2),y)
 IPUTILS_CONF_OPTS += -DUSE_IDN=true
-IPUTILS_DEPENDENCIES += libidn
+IPUTILS_DEPENDENCIES += libidn2
 else
 IPUTILS_CONF_OPTS += -DUSE_IDN=false
 endif