'--kunitconfig' option of 'kunit.py run' supports '.kunitconfig' file name
convention.  Add the file for DAMON kunit tests for more convenient kunit
run.

Link: https://lkml.kernel.org/r/20240827030336.7930-10-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>