DRM core driver has introduced recently fdinfo interface to
show memory stats of individual drm client. Lets interface
xe drm client to fdinfo interface.

V2:
  - cover call to xe_drm_client_fdinfo under PROC_FS
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>