Add system_ext to VINTF search paths.

Bug: 140280874
Test: pass

Change-Id: Ifd5b784fc3c4553284f74a1f06cbac0a9bef4c75
diff --git a/tools/releasetools/check_target_files_vintf.py b/tools/releasetools/check_target_files_vintf.py
index a556f53..f41df37 100755
--- a/tools/releasetools/check_target_files_vintf.py
+++ b/tools/releasetools/check_target_files_vintf.py
@@ -45,6 +45,7 @@
     '/vendor': ('VENDOR', 'SYSTEM/vendor'),
     '/product': ('PRODUCT', 'SYSTEM/product'),
     '/odm': ('ODM', 'VENDOR/odm', 'SYSTEM/vendor/odm'),
+    '/system_ext': ('SYSTEM_EXT', 'SYSTEM/system_ext'),
 }
 
 UNZIP_PATTERN = ['META/*', '*/build.prop']