mm/damon/sysfs: split out kdamond-independent schemes stats update logic into a new function

mainline inclusion
from mainline-v6.2-rc6
commit 4acd715f
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6MRUG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4acd715ff57fd05a481c64d074db68f2cf5711aa

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'damon_sysfs_schemes_update_stats()' is coupled with both
damon_sysfs_kdamond and damon_sysfs_schemes.  It's a wide range of types
dependency.  It makes splitting the logics a little bit distracting.
Split the function so that each function is coupled with smaller range of
types.

Link: https://lkml.kernel.org/r/20221026225943.100429-10-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ze Zuo <zuoze1@huawei.com>