drm/xe/display: fix oops in suspend/shutdown without display

In the Linux kernel, the following vulnerability has been resolved:

drm/xe/display: fix oops in suspend/shutdown without display

The xe driver keeps track of whether to probe display, and whether

display hardware is there, using xe->info.probe_display. It gets set to

false if there's no display after intel_display_device_probe(). However,

the display may also be disabled via fuses, detected at a later time in

intel_display_device_info_runtime_init().

In this case, the xe driver does for_each_intel_crtc() on uninitialized

mode config in xe_display_flush_cleanup_work(), leading to a NULL

pointer dereference, and generally calls display code with display info

cleared.

Check for intel_display_device_present() after

intel_display_device_info_runtime_init(), and reset

xe->info.probe_display as necessary. Also do unset_display_features()

for completeness, although display runtime init has already done

that. This will need to be unified across all cases later.

Move intel_display_device_info_runtime_init() call slightly earlier,

similar to i915, to avoid a bunch of unnecessary setup for no display

cases.

Note #1: The xe driver has no business doing low level display plumbing

like for_each_intel_crtc() to begin with. It all needs to happen in

display code.

Note #2: The actual bug is present already in commit 44e694958b95

("drm/xe/display: Implement display support"), but the oops was likely

introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display

suspend/resume work on discrete").

(cherry picked from commit 7c3eb9f47533220888a67266448185fd0775d4da)