mm/damon: rename damon_pageout_score() to damon_cold_score()

mainline inclusion
from mainline-v6.2-rc6
commit e3e486e6
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=e3e486e634bfd652036292c3d66f9d388614ffe6

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In the beginning there is only one damos_action 'DAMOS_PAGEOUT' that need
to get the coldness score of a region for a scheme, which using
damon_pageout_score() to do that.  But now there are also other
damos_action actions need the coldness score, so rename it to
damon_cold_score() to make more sense.

Link: https://lkml.kernel.org/r/1663423014-28907-1-git-send-email-kaixuxia@tencent.com


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