drm/xe/client: drop bogus bo NULL check

If we fished it out the list then it can't be null; the list entry is
embedded in the bo.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240318093431.21075-4-matthew.auld@intel.com

drivers/gpu/drm/xe/xe_drm_client.c

@@ -155,7 +155,7 @@ static void show_meminfo(struct drm_printer *p, struct drm_file *file)
 	/* Internal objects. */
 	spin_lock(&client->bos_lock);
 	list_for_each_entry(bo, &client->bos_list, client_link) {
-		if (!bo || !kref_get_unless_zero(&bo->ttm.base.refcount))
+		if (!kref_get_unless_zero(&bo->ttm.base.refcount))
 			continue;
 		bo_meminfo(bo, stats);
 		xe_bo_put(bo);