tools: Fix patman launcher script.

There is no "run_patman" procedure in patman's __main__.py file, which
would cause the following error at execution:

  "AttributeError: module 'patman.__main__' has no attribute 'run_patman'"

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/patman/pyproject.toml

@@ -23,7 +23,7 @@ classifiers = [
 "Bug Tracker" = "https://source.denx.de/groups/u-boot/-/issues"
 
 [project.scripts]
-patman = "patman.__main__:run_patman"
+patman = "patman.__main__"
 
 [tool.setuptools.package-data]
 patman = ["*.rst"]