cpuidle: Reject idle entry if need_resched() is true

There's no reason to enter idle at this point in __CPU_PM_CPU_IDLE_ENTER()
if the CPU needs to reschedule. Instead of fruitlessly entering the
architecture's idle routine, reject the idle entry attempt with an error as
an optimization.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>

include/linux/cpuidle.h

@@ -286,7 +286,9 @@ extern s64 cpuidle_governor_latency_req(unsigned int cpu);
 ({									\
 	int __ret = 0;							\
 									\
-	if (!idx) {							\
+	if (need_resched()) {						\
+		__ret = -1;						\
+	} else if (!idx) {						\
 		cpu_do_idle();						\
 		return idx;						\
 	}								\