mm/damon: add synchronous commit for commit_inputs

mm/damon: add synchronous commit for commit_inputs

Problem
=======
Writing invalid parameters to sysfs followed by 'commit_inputs=Y' fails
silently (no error returned to shell), because the validation happens
asynchronously in the kdamond.

Solution
========
To fix this, the commit_inputs_store() callback now uses damon_call() to
synchronously commit parameters in the kdamond thread's safe context.
This ensures that validation errors are returned immediately to
userspace, following the pattern used by DAMON_SYSFS.

Changes
=======
1. Added commit_inputs_store() and commit_inputs_fn() to commit
   synchronously.
2. Removed handle_commit_inputs().

This change is motivated from another discussion [1].

Link: https://lore.kernel.org/20260426231619.107231-4-sj@kernel.org
Link: https://lore.kernel.org/20260318153731.97470-1-aethernet65535@gmail.com
Signed-off-by: Liew Rui Yan <aethernet65535@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
Cc: Cheng-Han Wu <hank20010209@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>