ANDROID: fix kernelci issue for allnoconfig builds

'allnoconfig' builds failed with:

kernel/sched/sched.h:1203:50: error: ‘struct rq’ has no member named ‘cpu’

rq->cpu needs to be replaced with cpu_of(rq) for !CONFIG_SMP builds

Fixes: 4442801a43 ("ANDROID: sched: Introducing PELT multiplier")
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: Iceb439dc3bba27516b5ecd2c18c9835c23e5a39a

kernel/sched/sched.h

@@ -1200,7 +1200,7 @@ static inline u64 rq_clock_task_mult(struct rq *rq)
 	lockdep_assert_held(&rq->lock);
 	assert_clock_updated(rq);
 
-	return per_cpu(clock_task_mult, rq->cpu);
+	return per_cpu(clock_task_mult, cpu_of(rq));
 }
 
 /**