sched/smp: Use the SMP version of is_migration_disabled()

Simplify the scheduler by making the CONFIG_SMP-only code in
is_migration_disabled() unconditional.

Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Shrikanth Hegde <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: Vincent Guittot <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Ingo Molnar

kernel/sched/sched.h

@@ -1301,11 +1301,7 @@ static inline int cpu_of(struct rq *rq)
 
 static inline bool is_migration_disabled(struct task_struct *p)
 {
-#ifdef CONFIG_SMP
 	return p->migration_disabled;
-#else
-	return false;
-#endif
 }
 
 DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);