build: Update known-good files for 1.2.146 header

Changes:
- Updated `known_good.json`
- Added directfb to platform dictionary in `common_codegen.py`
- Generated new source files

Change-Id: I8dcc87d22036b2df068da0c5220a5e1158bbe07c
diff --git a/scripts/common_codegen.py b/scripts/common_codegen.py
index 11b4fe5..e7bfb9c 100644
--- a/scripts/common_codegen.py
+++ b/scripts/common_codegen.py
@@ -58,6 +58,7 @@
     'xlib' : 'VK_USE_PLATFORM_XLIB_KHR',
     'xlib_xrandr' : 'VK_USE_PLATFORM_XLIB_XRANDR_EXT',
     'provisional' : 'VK_ENABLE_BETA_EXTENSIONS',
+    'directfb' : 'VK_USE_PLATFORM_DIRECTFB_EXT',
 }
 
 #