This commit moves 'damon_set_regions()' from vaddr to core, as it is aimed
to be used by not only 'vaddr' but also other parts of DAMON.

Link: https://lkml.kernel.org/r/20220429160606.127307-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>