drm/i915: check for GT faults in all resume handlers and driver load time

Checking for GT faults is not specific in any way to S4 thaw, so do it
also during S3 resume, S4 restore and driver load time. This allows us to
unify the Sx handlers in an upcoming patch.

v2:
- move the check to intel_uncore_early_sanitize(), so we check at driver
  load time too (Chris)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>