accel/ivpu: Use lazy allocation for doorbell IDs

Reserve/allocate and free doorbells for command queues when needed
using xarray. This allows to avoid reserving a doorbell for
a contexts that never issues a job.

Signed-off-by: Wachowski, Karol <karol.wachowski@intel.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240214081305.290108-6-jacek.lawrynowicz@linux.intel.com