libmpeg2: add hash for license file

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

package/libmpeg2/libmpeg2.hash

@@ -1,2 +1,3 @@
 # Locally computed:
 sha256  dee22e893cb5fc2b2b6ebd60b88478ab8556cb3b93f9a0d7ce8f3b61851871d4  libmpeg2-0.5.1.tar.gz
+sha256  32b1062f7da84967e7019d01ab805935caa7ab7321a7ced0e30ebe75e5df1670  COPYING