mm/damon/tests/core-kunit: remove DAMON_MIN_REGION redefinition

mm/damon/tests/core-kunit: remove DAMON_MIN_REGION redefinition

A few DAMON core functions including damon_set_regions() were hard-coded
to use DAMON_MIN_REGION as their regions management granularity.  For
simple and human-readable unit tests' expectations, DAMON core layer kunit
test re-defines DAMON_MIN_REGION to '1'.

A previous patch series [1] has removed the hard-coded part but kept the
redefinition and updated related function calls to explicitly use
DAMON_MIN_REGION.  Remove the unnecessary redefinition and update relevant
function calls to pass literals (number '1') instead of the
DAMON_MIN_REGION.

Link: https://lkml.kernel.org/r/20251112154114.66053-7-sj@kernel.org
Link: https://lore.kernel.org/20250828171242.59810-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>