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/gen_app_partitions.py b/scripts/gen_app_partitions.py
index 0cc95ba..c5046c1 100644
--- a/scripts/gen_app_partitions.py
+++ b/scripts/gen_app_partitions.py
@@ -103,7 +103,7 @@
 def find_obj_file_partitions(filename, partitions):
     with open(filename, 'rb') as f:
         full_lib = ELFFile( f)
-        if (not full_lib):
+        if not full_lib:
             print("Error parsing file: ",filename)
             os.exit(1)