[bug report] drm/xe: Cleanup some layering in GGTT

[Dan Carpenter]

Hello Matthew Brost,

This is a semi-automatic email about new static checker warnings.

The patch 3121fed0c51b: "drm/xe: Cleanup some layering in GGTT" from
Feb 22, 2024, leads to the following Smatch complaint:

    drivers/gpu/drm/xe/xe_ggtt.c:256 ggtt_invalidate_gt_tlb()
    warn: variable dereferenced before check 'gt' (see line 253)

drivers/gpu/drm/xe/xe_ggtt.c
   252	{
   253		struct xe_device *xe = gt_to_xe(gt);
                                                ^^
The patch adds an unchecked dereference

   254		int err;
   255	
   256		if (!gt)
                    ^^^
Checked too late

   257			return;
   258	

regards,
dan carpenter