loader: gh1661 - Phys dev exts not loading

Fix a bug whereby commands from physical device extensions were
not being written to the instance extension dispatch table,
preventing their terminators from ever being run.

Change-Id: I38dab0ae6463674f2a1f572bc0ee1eebe8d0dd13
diff --git a/scripts/loader_extension_generator.py b/scripts/loader_extension_generator.py
index 0a0f04e..2194331 100644
--- a/scripts/loader_extension_generator.py
+++ b/scripts/loader_extension_generator.py
@@ -1243,7 +1243,7 @@
                 commands = self.ext_commands
 
             for cur_cmd in commands:
-                if cur_cmd.ext_type == 'instance':
+                if cur_cmd.ext_type == 'instance' or (cur_cmd.ext_type == 'device' and cur_cmd.handle_type == 'VkPhysicalDevice'):
                     if cur_cmd.ext_name != cur_extension_name:
                         if 'VK_VERSION_' in cur_cmd.ext_name:
                             table += '\n    // ---- Core %s commands\n' % cur_cmd.ext_name[11:]