layers: Complete support for VK_KHR_Display ext

Fixed using display extension only crash.
Added vkGetDisplayPlaneCapabilitiesKHR.
Fixes, that unique objects works for display extension.

Change-Id: I66727a430b9d55bfa40fdddc884f40c91aa29f11
diff --git a/scripts/vulkan.py b/scripts/vulkan.py
index 9000765..5d71f52 100644
--- a/scripts/vulkan.py
+++ b/scripts/vulkan.py
@@ -1375,6 +1375,7 @@
 common_exts = [VK_VERSION_1_0,
                VK_KHR_surface,
                VK_KHR_swapchain,
+               VK_KHR_display,
                VK_KHR_display_swapchain,
               ]
 
@@ -1398,8 +1399,7 @@
 #                    VK_AMD_shader_ballot,
 #                    VK_IMG_format_pvrtc,
                     ]
-non_android_exts = [VK_KHR_display,
-                   ]
+
 extensions = common_exts
 extensions_all = non_exported_exts