sched/irq/Make.defs: Fix warning about irq_csection.o appearing multiple times in the same rule.

sched/Kconfig

@@ -891,7 +891,6 @@ config SCHED_INSTRUMENTATION
 	default n
 	select SCHED_SUSPENDSCHEDULER
 	select SCHED_RESUMESCHEDULER
-	select IRQCOUNT
 	---help---
 		Enables instrumentation in scheduler to monitor system performance.
 		If enabled, then the board-specific logic must provide the following
@@ -938,6 +937,7 @@ config SCHED_INSTRUMENTATION_PREEMPTION
 config SCHED_INSTRUMENTATION_CSECTION
 	bool "Critical section monitor hooks"
 	default n
+	select IRQCOUNT
 	---help---
 		Enables additional hooks for entry and exit from critical sections.
 		Interrupts are disabled while within a critical section.  Board-

sched/irq/Make.defs

@@ -36,7 +36,6 @@
 CSRCS += irq_initialize.c irq_attach.c irq_dispatch.c irq_unexpectedisr.c
 
 ifeq ($(CONFIG_SMP),y)
-CSRCS += irq_csection.c
 ifeq ($(CONFIG_SPINLOCK_IRQ),y)
 ifeq ($(CONFIG_ARCH_GLOBAL_IRQDISABLE),y)
 CSRCS += irq_spinlock.c