layers: Fix safe_struct gen to skip debug_marker struct

Safe structure doesn't work with static arrays; add an
exception so safe-struct is not generated for the strcuture in question.

Change-Id: I4605fdfb3dd840fb8e38371e7e59311fc6e1cb9f
diff --git a/vk_helper.py b/vk_helper.py
index fc99b1c..62c1d1a 100755
--- a/vk_helper.py
+++ b/vk_helper.py
@@ -1548,7 +1548,7 @@
 
     # If struct has sType or ptr members, generate safe type
     def _hasSafeStruct(self, s):
-        exceptions = ['VkPhysicalDeviceFeatures', 'VkPipelineColorBlendStateCreateInfo']
+        exceptions = ['VkPhysicalDeviceFeatures', 'VkPipelineColorBlendStateCreateInfo', 'VkDebugMarkerMarkerInfoEXT']
         if s in exceptions:
             return False
         if 'sType' == self.struct_dict[s][0]['name']: