test: fix pydoc issues for EFI tests

Fix issues reported by pydocstyle.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/test/py/tests/test_efi_secboot/defs.py b/test/py/tests/test_efi_secboot/defs.py
index b7a2a11..6a2317e 100644
--- a/test/py/tests/test_efi_secboot/defs.py
+++ b/test/py/tests/test_efi_secboot/defs.py
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier:      GPL-2.0+
 
+"""Constants used for secure boot test."""
+
 # Owner guid
 GUID = '11111111-2222-3333-4444-123456789abc'