UPSTREAM: wqmm/damon/sysfs-schemes: support DAMOS apply interval

Update DAMON sysfs interface to support DAMOS apply intervals by adding a
new file, 'apply_interval_us' in each scheme directory.  Users can set and
get the interval for each scheme in microseconds by writing to and reading
from the file.

Link: https://lkml.kernel.org/r/20230916020945.47296-7-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit a2a9f68e)

Bug:361213181

Change-Id: I72b23f180559edf31d22852d31e7bdc2993a7b97
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Zhanbo Xiong <xiongzhanbo@xiaomi.corp-partner.google.com>