.dsw files are Visual Studio stuff

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/check-files.py b/tests/scripts/check-files.py
index de4d245..5bec6db 100755
--- a/tests/scripts/check-files.py
+++ b/tests/scripts/check-files.py
@@ -137,7 +137,7 @@
 
 def is_windows_file(filepath):
     _root, ext = os.path.splitext(filepath)
-    return ext in ('.bat', '.dsp', '.sln', '.vcxproj')
+    return ext in ('.bat', '.dsp', '.dsw', '.sln', '.vcxproj')
 
 
 class PermissionIssueTracker(FileIssueTracker):