systemd: Fix polkit build order

We need to install polkit before systemd if we want to enable
polkit integration, because systemd will not install polkit
policy files unless it finds polkit-gobject-1.

Signed-off-by: Asgeir Bjarni Ingvarsson <asgeir@appdynamic.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/systemd/systemd.mk

@@ -283,6 +283,7 @@ endif
 
 ifeq ($(BR2_PACKAGE_SYSTEMD_POLKIT),y)
 SYSTEMD_CONF_OPTS += -Dpolkit=true
+SYSTEMD_DEPENDENCIES += polkit
 else
 SYSTEMD_CONF_OPTS += -Dpolkit=false
 endif