vulkan/wsi/wayland: Fix proxy wrappers for swapchain recreation

vulkan/wsi/wayland: Fix proxy wrappers for swapchain recreation

Before the swapchain event queue is destroyed, all proxy objects that reference
it must be dropped. Otherwise we risk a use-after-free if a frame callback event
or buffer release events are received afterwards.
This happens when an application destroys and recreates a swapchain in FIFO
mode between two frames without using the VkSwapchainCreateInfoKHR::oldSwapchain
mechanism to keep the old swapchain until after the next redraw.

Fixes: 5034c615582a ("vulkan/wsi/wayland: Use proxy wrappers for swapchain")
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Cc: mesa-stable@lists.freedesktop.org