drm/xe/display: Extract xe_display_pm_runtime_suspend_late()

drm/xe/display: Extract xe_display_pm_runtime_suspend_late()

The current behavior for the runtime suspend case is that
xe_display_pm_suspend_late() is only called when D3cold is allowed.
Let's incorporate that behavior into a function specific to runtime PM
and call it xe_display_pm_runtime_suspend_late().

With that, we keep stuff a bit more self-contained and allow having a
place for adding more "late display runtime suspend"-related logic that
isn't dependent on the "D3cold allowed" state.

v2:
  - Fix typo in that caused xe_display_pm_runtime_suspend_late() to call
    itself instead of xe_display_pm_suspend_late().
  - Add the empty version of xe_display_pm_runtime_suspend_late() for
    the !CONFIG_DRM_XE_DISPLAY case.

Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241129164010.29887-3-gustavo.sousa@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>