sched/fair: Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()

Andy reported that clang gets upset with CONFIG_CFS_BANDWIDTH=n:

  kernel/sched/fair.c:6580:20: error: unused function 'cfs_bandwidth_used' [-Werror,-Wunused-function]
   6580 | static inline bool cfs_bandwidth_used(void)
	|                    ^~~~~~~~~~~~~~~~~~

Indeed, cfs_bandwidth_used() is only used within functions defined under
CONFIG_CFS_BANDWIDTH=y. Remove its CONFIG_CFS_BANDWIDTH=n declaration &
definition.

Reported-by: Andy Shevchenko <[email protected]>
Signed-off-by: Valentin Schneider <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: valschneider

kernel/sched/fair.c

@@ -5373,8 +5373,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
 static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
 static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq);
 
-static inline bool cfs_bandwidth_used(void);
-
 static void
 requeue_delayed_entity(struct sched_entity *se);
 
@@ -6748,11 +6746,6 @@ static void sched_fair_update_stop_tick(struct rq *rq, struct task_struct *p)
 
 #else /* CONFIG_CFS_BANDWIDTH */
 
-static inline bool cfs_bandwidth_used(void)
-{
-	return false;
-}
-
 static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {}
 static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; }
 static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}