perl: add hash for the perl-cross file

Fix:
  WARNING: No hash found for perl-5.20.1-cross-0.9.4.tar.gz

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/perl/perl.hash

@@ -2,3 +2,6 @@
 md5    ede5166f949d9a07163bc5b086be9759                                 perl-5.20.1.tar.bz2
 sha1   cd424d1520ba2686fe5d4422565aaf880e9467f6                         perl-5.20.1.tar.bz2
 sha256 ede5ded37e7fb6139b04728cfca826f17076f9888dbfd100a56834dbeb04657c perl-5.20.1.tar.bz2
+
+# No upstream hashes for the following
+sha256 614f320d45042ca179a15ec88c6a15ff68e6f36fb004ee89efa71e42bda1dead perl-5.20.1-cross-0.9.4.tar.gz