package/s390-tools: fix license

Fix license file name in hash file

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/s390-tools/s390-tools.hash

@@ -1,3 +1,3 @@
 # Locally computed:
 sha256  8dc1180031018756ccd5acf6c26c4175bcac79e512e8a2ea8569fdf5d3f9bd6c  s390-tools-2.15.1.tar.gz
-sha256  cca17a9a944ebec769adee4aebd805c912c357785ff2705a99ffe68563021f75  COPYING
+sha256  cca17a9a944ebec769adee4aebd805c912c357785ff2705a99ffe68563021f75  LICENSE