mm/damon/paddr: remove damon_pa_access_chk_result struct

'damon_pa_access_chk_result' struct contains only one field.  Use a
variable instead.

Link: https://lkml.kernel.org/r/20230109213335.62525-7-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>