package/libffi: add license hash

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/libffi/libffi.hash

@@ -1,2 +1,4 @@
 # From ftp://sourceware.org/pub/libffi/sha512.sum
 sha512	980ca30a8d76f963fca722432b1fe5af77d7a4e4d2eac5144fbc5374d4c596609a293440573f4294207e1bdd9fda80ad1e1cafb2ffb543df5a275bc3bd546483  libffi-3.2.1.tar.gz
+# License files, locally calculated
+sha256	0f4d7a0bfb83c37465d42dc305f124189196cc0cc2cc8d6f8461103682aebbc5  LICENSE