support converting interfaces with parameters

test/basic/interface_func.sv

@@ -1,11 +1,16 @@
 interface Foo;
-    function bar;
+    parameter MULTIPLIER = 7;
+    function integer bar;
         input integer x;
-        return x * x;
+        return x * x * MULTIPLIER;
     endfunction
 endinterface
 
 module top;
-    Foo foo();
-    initial $display(foo.bar(3));
+    Foo foo_1();
+    Foo #(.MULTIPLIER(8)) foo_2();
+    initial begin
+        $display(foo_1.bar(3));
+        $display(foo_2.bar(3));
+    end
 endmodule