mm/damon/core: mark damon_moving_sum() as a static function

The function is used by only mm/damon/core.c.  Mark it as a static
function.

Link: https://lkml.kernel.org/r/20230915025251.72816-9-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/damon.h

@@ -632,8 +632,6 @@ void damon_add_region(struct damon_region *r, struct damon_target *t);
 void damon_destroy_region(struct damon_region *r, struct damon_target *t);
 int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
 		unsigned int nr_ranges);
-unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum,
-		unsigned int len_window, unsigned int new_value);
 void damon_update_region_access_rate(struct damon_region *r, bool accessed,
 		struct damon_attrs *attrs);
 

mm/damon/core.c

@@ -1587,7 +1587,7 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t,
  *
  * Return: Pseudo-moving average after getting the @new_value.
  */
-unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum,
+static unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum,
 		unsigned int len_window, unsigned int new_value)
 {
 	return mvsum - nomvsum / len_window + new_value;