Check scripts/mbedtls_dev/*.py with pylint

mypy automatically checks the modules when it encounters them as
imports. Don't make it check them twice, because it would complain
about encountering them through different paths (via the command line
as scripts/mbedtls_dev/*.py and via imports as just mbedtls_dev/*.py).

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/check-python-files.sh b/tests/scripts/check-python-files.sh
index a80860d..8f8026e 100755
--- a/tests/scripts/check-python-files.sh
+++ b/tests/scripts/check-python-files.sh
@@ -28,7 +28,7 @@
     PYTHON=python
 fi
 
-$PYTHON -m pylint -j 2 scripts/*.py tests/scripts/*.py || {
+$PYTHON -m pylint -j 2 scripts/mbedtls_dev/*.py scripts/*.py tests/scripts/*.py || {
     echo >&2 "pylint reported errors"
     ret=1
 }