drm/xe: Delete unused GuC submission_state.suspend

GuC submission_state.suspend is unused, delete it.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240425054747.1918811-1-matthew.brost@intel.com