opus-tools: add hash for license file

Signed-off-by: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/opus-tools/opus-tools.hash

@@ -1,2 +1,5 @@
 # From http://downloads.xiph.org/releases/opus/SHA256SUMS.txt
 sha256 a2357532d19471b70666e0e0ec17d514246d8b3cb2eb168f68bb0f6fd372b28c  opus-tools-0.1.10.tar.gz
+
+# Hash for license file
+sha256 88021117568c64038175d7fb3b8286056f7cdb54f09dc806578f6bd9342c62cc  COPYING