tools: patman: fix deprecated Python ConfigParser methods

The method `ConfigParser.readfp()` is marked deprecated[1].

In Python 3.12 this method have been removed, so replace it with
`ConfigParser.read_file()`.

[1] https://docs.python.org/3.11/library/configparser.html#configparser.ConfigParser.readfp

Signed-off-by: Brandon Maier <brandon.maier@collins.com>
CC: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed