[PATCH for-mm-unstable] kernel/sched/fair: include missed header file, memory-tiers.h

[SeongJae Park <sj@kernel.org>]

Commit f66f3c261487 ("mm/demotion: update node_is_toptier to work with
memory tiers") of the 'mm-unstable' tree moved the declaration of
'node_is_toptier()' from 'node.h' to 'memory-tiers.h' but didn't include
the header in a source file using the function, 'kernel/sched/fair.c'.
As a result, build fails as below:

    linux/kernel/sched/fair.c: In function ‘should_numa_migrate_memory’:
    linux/kernel/sched/fair.c:1571:7: error: implicit declaration of function ‘node_is_toptier’ [-Werror=implicit-function-declaration]
     1571 |      !node_is_toptier(src_nid)) {
          |       ^~~~~~~~~~~~~~~
    cc1: some warnings being treated as errors

This commit fixes the error by including the missed header file.

Fixes: f66f3c261487 ("mm/demotion: update node_is_toptier to work with memory tiers") on mm-unstable
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 kernel/sched/fair.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d642e9ff2829..0e3e08a093d4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -40,6 +40,7 @@
 
 #include <linux/cpuidle.h>
 #include <linux/interrupt.h>
+#include <linux/memory-tiers.h>
 #include <linux/mempolicy.h>
 #include <linux/mutex_api.h>
 #include <linux/profile.h>
-- 
2.25.1