drm/xe: remove unmatched xe_vm_unlock() from __xe_exec_queue_init()

There is unmatched xe_vm_unlock() in the __xe_exec_queue_init().
Leftover from commit fbeaad07 ("drm/xe: Create LRC BO without VM")

Fixes: fbeaad07 ("drm/xe: Create LRC BO without VM")
Signed-off-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Link: https://lore.kernel.org/r/20250530135627.2821612-1-maciej.patelczyk@intel.com