sched/fair: Remove useless check in select_idle_core()

The function select_idle_core() only gets called when has_idle_cores
is true which can be possible only when sched_smt_present is enabled.

This change also aligns select_idle_core() with select_idle_smt() in
the way that the caller do the check if necessary.
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20220907112000.1854-4-wuyun.abel@bytedance.com

kernel/sched/fair.c

@@ -6321,9 +6321,6 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu
 	bool idle = true;
 	int cpu;
 
-	if (!static_branch_likely(&sched_smt_present))
-		return __select_idle_cpu(core, p);
-
 	for_each_cpu(cpu, cpu_smt_mask(core)) {
 		if (!available_idle_cpu(cpu)) {
 			idle = false;