pylint: Adjust how the output is produced

The current Makefile rule requires there to be a 'Module' line in the
pylint output, like this:

   ************* Module binman.fip_util

This line only appears if pylint has some comments about the module. We
cannot rely on it for naming.

Update the code to instead use the filename as the identifier for each
score, so rather than:

   multiplexed_log 7.49

we output:

   test_multiplexed_log.py 7.20

It is still easy to see which file the score relates to. In fact the new
naming is nicer since the full subdirectories are shown.

The avoids the problem where a module name is not produced, and the output
gets out of sync.

Regenerate pylint.base so we can start from the current baseline.

Signed-off-by: Simon Glass <sjg@chromium.org>