iris: Don't leak the resource for unsupported modifier

Make sure the res struct is free'd before returning.

Fixes: 2dce0e94a3 ("iris: Initial commit of a new 'iris' driver for Intel Gen8+ GPUs.")
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit f2fc5dece9)

src/gallium/drivers/iris/iris_resource.c

@@ -717,7 +717,7 @@ iris_resource_create_with_modifiers(struct pipe_screen *pscreen,
    } else {
       if (modifiers_count > 0) {
          fprintf(stderr, "Unsupported modifier, resource creation failed.\n");
-         return NULL;
+         goto fail;
       }
 
       /* No modifiers - we can select our own tiling. */