UPSTREAM: mm/damon: remove return value from before_terminate callback

Since the return value of 'before_terminate' callback is never used, we
make it have no return value.

Link: https://lkml.kernel.org/r/20211029005023.8895-1-changbin.du@gmail.com


Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 658f9ae7)

Bug: 228223814
Signed-off-by: Hailong Tu <tuhailong@oppo.com>
Change-Id: Ida44623827a7a667118a2af329f6e58a57941fc9