mm/damon/sysfs: remove parameters of damon_sysfs_region_alloc()

'damon_sysfs_region_alloc()' is always called with zero-filled 'struct
damon_addr_range', because the start and end addresses should set by
users.  Remove unnecessary parameters of the function and simplify the
body by using 'kzalloc()'.

Link: https://lkml.kernel.org/r/20221026225943.100429-7-sj@kernel.org


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