drm/xe: Move part of xe_file cleanup to a helper

drm/xe: Move part of xe_file cleanup to a helper

In order to make xe_file ref counted, move destruction of xe_file
members to a helper.

v2: Move xe_vm_close_and_put back into xe_file_close (Matt)

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240718210548.3580382-2-umesh.nerlige.ramappa@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>