opus: add hash

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/opus/opus.hash

@@ -0,0 +1,2 @@
+# From http://downloads.xiph.org/releases/opus/SHA256SUMS.txt
+sha256	b9727015a58affcf3db527322bf8c4d2fcf39f5f6b8f15dbceca20206cbe1d95	opus-1.1.tar.gz