intel: fix an assertion in create info copying

XGL_VIEWPORT_STATE_CREATE_INFO has no header and we should not assert
info.header->next to be NULL.
diff --git a/icd/intel/obj.c b/icd/intel/obj.c
index b0aa05b..d5d3250 100644
--- a/icd/intel/obj.c
+++ b/icd/intel/obj.c
@@ -166,7 +166,9 @@
     }
 
     if (shallow_copy) {
-        assert(!info.header->next);
+        /* XGL_VIEWPORT_STATE_CREATE_INFO has no header */
+        if (dbg->type != XGL_DBG_OBJECT_VIEWPORT_STATE)
+            assert(!info.header->next);
 
         dbg->create_info = icd_alloc(shallow_copy, 0, XGL_SYSTEM_ALLOC_DEBUG);
         if (!dbg->create_info)