binman: fallback to importlib_resources on Python 3.8

Python 3.7 and 3.8 lack the files attribute in importlib.resources.
Use importlib_resources to fix build errors with Python 3.8:
binman: module 'importlib.resources' has no attribute 'files'

Fixes: 538719cb6a77 ("binman: migrate from pkg_resources to importlib")
Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
Acked-by: Quentin Schulz <quentin.schulz@cherry.de>
[trini: Re-add # pragma: no cover line]
Signed-off-by: Tom Rini <trini@konsulko.com>

tools/binman/control.py

@@ -9,8 +9,9 @@ from collections import OrderedDict
 import glob
 try:
     import importlib.resources as importlib_resources
-except ImportError:  # pragma: no cover
-    # for Python 3.6
+    # for Python 3.6, 3.7 and 3.8
+    importlib_resources.files
+except (ImportError, AttributeError): # pragma: no cover
     import importlib_resources
 import os
 import re