drm/xe: remove unused struct 'xe_gt_desc'

'xe_gt_desc' is unused since
commit 1e6c20be ("drm/xe: Drop extra_gts[] declarations and
XE_GT_TYPE_REMOTE").

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link:
https://patchwork.freedesktop.org/patch/msgid/20240522175840.382107-1-linux@treblig.org


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>