turnip: free up hwvulkan_device_t upon driver unloading

Per <hardware/hwvulkan.h>, the hw_device_t::close() function is called
upon driver unloading. The behavior has been like this since Android 10.

Acked-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35561>

src/freedreno/vulkan/tu_android.cc

@@ -76,7 +76,13 @@ tu_hal_open(const struct hw_module_t *mod,
 static int
 tu_hal_close(struct hw_device_t *dev)
 {
-   /* hwvulkan.h claims that hw_device_t::close() is never called. */
+   /* the hw_device_t::close() function is called upon driver unloading */
+   assert(dev->version == HWVULKAN_DEVICE_API_VERSION_0_1);
+   assert(dev->module == &HAL_MODULE_INFO_SYM.common);
+
    vk_android_destroy_ugralloc();
-   return -1;
+
+   hwvulkan_device_t *hal_dev = container_of(dev, hwvulkan_device_t, common);
+   free(hal_dev);
+   return 0;
 }