MN10300: Delete idle_timestamp from irq_cpustat_t

Delete idle_timestamp from irq_cpustat_t as it's an unread relic.
Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>

arch/mn10300/include/asm/hardirq.h

@@ -19,7 +19,6 @@
 /* assembly code in softirq.h is sensitive to the offsets of these fields */
 typedef struct {
 	unsigned int	__softirq_pending;
-	unsigned long	idle_timestamp;
 	unsigned int	__nmi_count;	/* arch dependent */
 	unsigned int	__irq_count;	/* arch dependent */
 } ____cacheline_aligned irq_cpustat_t;

arch/mn10300/kernel/process.c

@@ -88,8 +88,6 @@ void cpu_idle(void)
 			idle = pm_idle;
 			if (!idle)
 				idle = default_idle;
-
-			irq_stat[cpu].idle_timestamp = jiffies;
 			idle();
 		}