systemd: add license information

Signed-off-by: Phil Eichinger <phil@zankapfel.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/systemd/systemd.mk

@@ -7,6 +7,8 @@
 SYSTEMD_VERSION = 44
 SYSTEMD_SITE = http://www.freedesktop.org/software/systemd/
 SYSTEMD_SOURCE = systemd-$(SYSTEMD_VERSION).tar.xz
+SYSTEMD_LICENSE = GPLv2+
+SYSTEMD_LICENSE_FILES = LICENSE
 SYSTEMD_INSTALL_STAGING = YES
 SYSTEMD_DEPENDENCIES = \
 	host-intltool \