drm/xe: Fix memory use after free

The wait_event_timeout() on g2h_fence.wq which is declared on
stack can return before the wake_up() gets called, resulting in a
stack out of bound access when wake_up() accesses the g2h_fene.wq.

Do not declare g2h_fence related wait_queue_head_t on stack.

Fixes the below KASAN BUG and associated kernel crashes.

BUG: KASAN: stack-out-of-bounds in do_raw_spin_lock+0x6f/0x1e0
Read of size 4 at addr ffff88826252f4ac by task kworker/u128:5/467

CPU: 25 PID: 467 Comm: kworker/u128:5 Tainted: G  U 6.3.0-rc4-xe #1
Workqueue: events_unbound g2h_worker_func [xe]
Call Trace:
 <TASK>
 dump_stack_lvl+0x64/0xb0
 print_report+0xc2/0x600
 kasan_report+0x96/0xc0
 do_raw_spin_lock+0x6f/0x1e0
 _raw_spin_lock_irqsave+0x47/0x60
 __wake_up_common_lock+0xc0/0x150
 dequeue_one_g2h+0x20f/0x6a0 [xe]
 g2h_worker_func+0xa9/0x180 [xe]
 process_one_work+0x527/0x990
 worker_thread+0x2d1/0x640
 kthread+0x174/0x1b0
 ret_from_fork+0x29/0x50
 </TASK>

Tested-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Bruce Chang <yu.bruce.chang@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>