st/mesa: free TGSI tokens with ureg_free_tokens()

since they're allocated by ureg_get_tokens().

NOTE: This is a candidate for the 8.0 and 9.0 branches.

src/mesa/state_tracker/st_mesa_to_tgsi.c

@@ -1259,5 +1259,5 @@ out:
 void
 st_free_tokens(const struct tgsi_token *tokens)
 {
-   free((void *)tokens);
+   ureg_free_tokens(tokens);
 }