util/u_queue: add an option to resize the queue when it's full

util/u_queue: add an option to resize the queue when it's full

Consider the following situation:
  mtx_lock(mutex);
  do_something();
  util_queue_add_job(...);
  mtx_unlock(mutex);

If the queue is full, util_queue_add_job will wait for a free slot.
If the job which is currently being executed tries to lock the mutex,
it will be stuck forever, because util_queue_add_job is stuck.

The deadlock can be trivially resolved by increasing the queue size
(reallocating the queue) in util_queue_add_job if the queue is full.
Then util_queue_add_job becomes wait-free.

radeonsi will use it.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>