'damon_va_apply_three_regions()' is just a wrapper of its general version,
'damon_set_regions()'.  This commit replaces the wrapper calls to directly
call the general version.

Link: https://lkml.kernel.org/r/20220429160606.127307-6-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>