radv: Implement vkGetSwapchainGrallocUsage2ANDROID.

radv: Implement vkGetSwapchainGrallocUsage2ANDROID.

This was implemented in version 6 of the VK_ANDROID_native_buffer
extension and we only implement version 5. However, the Android
Vulkan loader only checks whether vkGetInstanceProcAddr for the
function is not NULL.

This all went wrong when we switched to the layer code from ANV.
Because the function may now be different per device, it adds fallback
functions that dispatch to the dispatch table. So if we didn't implement
the function we still returned a pointer to the dispatch function,
which made the Android Vulkan loader believe it was supported.

Dispatch functions:
https://gitlab.freedesktop.org/mesa/mesa/-/blob/d555794f3032594dbef3623052103900138d2356/src/amd/vulkan/radv_entrypoints_gen.py#L328

Fixes: d555794f303 "radv: update entrypoints generation from ANV"
Gitlab: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2936
Acked-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5198>