scripts: Remove unnecessary () around if/while conditions in Python

Not needed in Python. Detected by check C0325 in pylint3.

Also replace an

  if len(tag):

with just

  if tag:

Empty strings, byte strings, lists, etc., are falsy in Python.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
diff --git a/scripts/kconfig/kconfigfunctions.py b/scripts/kconfig/kconfigfunctions.py
index 51ff54e..c612da1 100644
--- a/scripts/kconfig/kconfigfunctions.py
+++ b/scripts/kconfig/kconfigfunctions.py
@@ -12,7 +12,7 @@
 doc_mode = os.environ.get('KCONFIG_DOC_MODE') == "1"
 
 dt_defines = {}
-if (not doc_mode):
+if not doc_mode:
     # The env var 'GENERATED_DTS_BOARD_CONF' must be set unless we are in
     # doc mode
     GENERATED_DTS_BOARD_CONF = os.environ['GENERATED_DTS_BOARD_CONF']