libmnl: add hash for license file

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libmnl/libmnl.hash

@@ -1,3 +1,6 @@
 # From ftp://ftp.netfilter.org/pub/libmnl/libmnl-1.0.4.tar.bz2.{md5sum,sha1sum}
 md5	be9b4b5328c6da1bda565ac5dffadb2d	libmnl-1.0.4.tar.bz2
 sha1	2db40dea612e88c62fd321906be40ab5f8f1685a	libmnl-1.0.4.tar.bz2
+
+# Hash for license file:
+sha256	dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551	COPYING