Tools: Fix script logging

Fix issue preventing scripts respecting --log_level argument, by adding
a non-default handler. Also, add script name to log output.

Change-Id: I100a5c29276d362dc38cd6c46f472e5991873293
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/tools/modules/arg_utils.py b/tools/modules/arg_utils.py
index 80093a7..c0482b7 100644
--- a/tools/modules/arg_utils.py
+++ b/tools/modules/arg_utils.py
@@ -8,7 +8,7 @@
 import argparse
 
 import logging
-logger = logging.getLogger("TF-M")
+logger = logging.getLogger("TF-M.{}".format(__name__))
 
 from elftools.elf.elffile import ELFFile
 from file_loader import load_bytes_from_file