modify host attention impl accounting for score_mod

example/ck_tile/18_flexattn/fmha_fwd.cpp

@@ -1375,6 +1375,15 @@ bool run(const ck_tile::ArgParser& arg_parser)
             ck_tile::identity{},
             ck_tile::scales(scale_s));
 
+        auto score_mod = [] (auto score, ck_tile::index_t b, ck_tile::index_t h, ck_tile::index_t q_idx, ck_tile::index_t v_idx) {
+            (void) score; (void) b; (void) h; (void) q_idx; (void) v_idx;
+            return score;
+        };
+
+        s_host_ref.ForEach([&](auto& self, auto i) { 
+            self(i) = score_mod(self(i), i[0], i[1], i[2], i[3]);
+        });
+
         if(bias.type == bias_enum::elementwise_bias)
         {
             // elementwise bias