sched_ext: Relocate scx_enabled() related code

scx_enabled() will be used in scx_rq_clock_update/invalidate()
in the following patch, so relocate the scx_enabled() related code
to the proper location.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: Changwoo Min

kernel/sched/sched.h

@@ -1717,6 +1717,19 @@ struct rq_flags {
 
 extern struct balance_callback balance_push_callback;
 
+#ifdef CONFIG_SCHED_CLASS_EXT
+extern const struct sched_class ext_sched_class;
+
+DECLARE_STATIC_KEY_FALSE(__scx_ops_enabled);	/* SCX BPF scheduler loaded */
+DECLARE_STATIC_KEY_FALSE(__scx_switched_all);	/* all fair class tasks on SCX */
+
+#define scx_enabled()		static_branch_unlikely(&__scx_ops_enabled)
+#define scx_switched_all()	static_branch_unlikely(&__scx_switched_all)
+#else /* !CONFIG_SCHED_CLASS_EXT */
+#define scx_enabled()		false
+#define scx_switched_all()	false
+#endif /* !CONFIG_SCHED_CLASS_EXT */
+
 /*
  * Lockdep annotation that avoids accidental unlocks; it's like a
  * sticky/continuous lockdep_assert_held().
@@ -2505,19 +2518,6 @@ extern const struct sched_class rt_sched_class;
 extern const struct sched_class fair_sched_class;
 extern const struct sched_class idle_sched_class;
 
-#ifdef CONFIG_SCHED_CLASS_EXT
-extern const struct sched_class ext_sched_class;
-
-DECLARE_STATIC_KEY_FALSE(__scx_ops_enabled);	/* SCX BPF scheduler loaded */
-DECLARE_STATIC_KEY_FALSE(__scx_switched_all);	/* all fair class tasks on SCX */
-
-#define scx_enabled()		static_branch_unlikely(&__scx_ops_enabled)
-#define scx_switched_all()	static_branch_unlikely(&__scx_switched_all)
-#else /* !CONFIG_SCHED_CLASS_EXT */
-#define scx_enabled()		false
-#define scx_switched_all()	false
-#endif /* !CONFIG_SCHED_CLASS_EXT */
-
 /*
  * Iterate only active classes. SCX can take over all fair tasks or be
  * completely disabled. If the former, skip fair. If the latter, skip SCX.