mm/damon/reclaim: use 'struct damon_attrs' for storing parameters for it

DAMON_RECLAIM receives monitoring attributes by parameters one by one to
separate variables, and then combine those into 'struct damon_attrs'. 
This commit makes the module directly stores the parameter values to a
static 'struct damon_attrs' variable and use it to simplify the code.

Link: https://lkml.kernel.org/r/20220913174449.50645-8-sj@kernel.org


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