drm/i915: Update shared stats to use the new gem helper

Switch to using the new gem shared memory stats helper
rather than hand rolling it.

Link: https://lore.kernel.org/all/20231207180225.439482-1-alexander.deucher@amd.com/Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/i915/i915_drm_client.c

@@ -53,7 +53,7 @@ obj_meminfo(struct drm_i915_gem_object *obj,
 					obj->mm.region->id : INTEL_REGION_SMEM;
 	const u64 sz = obj->base.size;
 
-	if (obj->base.handle_count > 1)
+	if (drm_gem_object_is_shared_for_memory_stats(&obj->base))
 		stats[id].shared += sz;
 	else
 		stats[id].private += sz;