venus: enable timeline semaphore feedback

venus: enable timeline semaphore feedback

At vkQueueSubmit time, for each batch with timeline semaphores to
signal, append cmd_buffers with feedback cmds to update the counter
value in its respective feedback slot.

Since multiple signals on the same semaphore could be pending at the
same time across batches/vkQueueSubmits, src slots and commands are
allocated on demand. These src slots can be reused after they've been
signaled (if the current semaphore counter is greater/equal than the
src value) and are cleaned up on vkDestroySemaphore.

Signed-off-by: Juston Li <justonli@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20500>