Update arrayfire submodule to latest on 3.6 branch

pradeep · pradeep · commit a79a92937f15 · 2018-09-20T11:18:25.000+05:30
diff --git a/arrayfire b/arrayfire
@@ -1 +1 @@
-Subproject commit 4679623dc8ed0dfb8245bcda6e2d3f4a4f075db4
+Subproject commit 96fb54b20dffe5693ae5c3f8d7c20b5700a2b61d
