sched/smp: Use the SMP version of ENQUEUE_MIGRATED

Simplify the scheduler by making the CONFIG_SMP-only ENQUEUE_MIGRATED
flag unconditional.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20250528080924.2273858-42-mingo@kernel.org

Author: ingomolnar

kernel/sched/sched.h

@@ -2319,11 +2319,7 @@ extern const u32		sched_prio_to_wmult[40];
 
 #define ENQUEUE_HEAD		0x10
 #define ENQUEUE_REPLENISH	0x20
-#ifdef CONFIG_SMP
 #define ENQUEUE_MIGRATED	0x40
-#else
-#define ENQUEUE_MIGRATED	0x00
-#endif
 #define ENQUEUE_INITIAL		0x80
 #define ENQUEUE_MIGRATING	0x100
 #define ENQUEUE_DELAYED		0x200