gfxstream: 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>
1 file changed