libiio: fix libavahi-client dependency

Avahi needs avahi-daemon and D-Bus to build avahi-client.
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit 18e00edb7796790b1ac1a0f6982ab8e25e27c691)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libiio/libiio.mk

@@ -54,8 +54,8 @@ else
 LIBIIO_CONF_OPTS += -DWITH_IIOD_USBD=OFF
 endif
 
-# Avahi support in libiio requires avahi-client, which needs avahi-daemon
-ifeq ($(BR2_PACKAGE_AVAHI)$(BR2_PACKAGE_AVAHI_DAEMON),yy)
+# Avahi support in libiio requires avahi-client, which needs avahi-daemon and dbus
+ifeq ($(BR2_PACKAGE_AVAHI_DAEMON)$(BR2_PACKAGE_DBUS),yy)
 LIBIIO_DEPENDENCIES += avahi
 endif