ofono: fix missing systemd and dbus files

Ofono's service file was not being installed when systemd was selected
as the init system.

Without ofono.conf in /etc/dbus-1/system.d, ofonod cannot take its
dbus name on the system bus and will fail to start with a permission
denied error.

Signed-off-by: Mike Williams <mike@mikebwilliams.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ofono/ofono.mk

@@ -16,7 +16,10 @@ OFONO_DEPENDENCIES = \
 	libcap-ng \
 	mobile-broadband-provider-info
 
-OFONO_CONF_OPTS = --disable-test
+OFONO_CONF_OPTS = \
+	--disable-test \
+	--with-dbusconfdir=/etc \
+	$(if $(BR2_INIT_SYSTEMD),--with-systemdunitdir=/usr/lib/systemd/system)
 
 # N.B. Qualcomm QMI modem support requires O_CLOEXEC; so
 # make sure that it is defined.