drm/xe: Remove async worker and rework sync binds

Async worker is gone. All jobs and memory allocations done in IOCTL to
align with dma fencing rules.

Async vs. sync now means when do bind operations complete relative to
the IOCTL. Async completes when out-syncs signal while sync completes
when the IOCTL returns. In-syncs and out-syncs are only allowed in async
mode.

If memory allocations fail in the job creation step the VM is killed.
This is temporary, eventually a proper unwind will be done and VM will
be usable.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>