gst-plugins-good: add legal info

Signed-off-by: Gustavo Zacarias <gustavo.zacarias@free-electrons.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gstreamer/gst-plugins-good/gst-plugins-good.mk

@@ -7,6 +7,8 @@
 GST_PLUGINS_GOOD_VERSION = 0.10.31
 GST_PLUGINS_GOOD_SOURCE = gst-plugins-good-$(GST_PLUGINS_GOOD_VERSION).tar.xz
 GST_PLUGINS_GOOD_SITE = http://gstreamer.freedesktop.org/src/gst-plugins-good
+GST_PLUGINS_GOOD_LICENSE = LGPLv2.1+
+GST_PLUGINS_GOOD_LICENSE_FILES = COPYING
 
 GST_PLUGINS_GOOD_CONF_OPTS = \
 	--disable-examples \