mm/vmstat: remove unneeded return value

The return value of pagetypeinfo_showfree and pagetypeinfo_showblockcount
are unused now.  Remove them.

Link: https://lkml.kernel.org/r/20210715122911.15700-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmstat.c

@@ -1454,7 +1454,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,
 }
 
 /* Print out the free pages at each order for each migatetype */
-static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
+static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
 {
 	int order;
 	pg_data_t *pgdat = (pg_data_t *)arg;
@@ -1466,8 +1466,6 @@ static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 	seq_putc(m, '\n');
 
 	walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
-
-	return 0;
 }
 
 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
@@ -1503,7 +1501,7 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 }
 
 /* Print out the number of pageblocks for each migratetype */
-static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
+static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 {
 	int mtype;
 	pg_data_t *pgdat = (pg_data_t *)arg;
@@ -1514,8 +1512,6 @@ static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 	seq_putc(m, '\n');
 	walk_zones_in_node(m, pgdat, true, false,
 		pagetypeinfo_showblockcount_print);
-
-	return 0;
 }
 
 /*