genirq: Remove redundant NULL check of irq_desc

for_each_irq_desc() macro has already skipped NULL irq_desc, don't
bother to check it again.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Cc: mingo@kernel.org
Cc: yhlu.kernel@gmail.com
Link: http://lkml.kernel.org/r/1458395959-7046-1-git-send-email-nasa4836@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/proc.c

@@ -421,12 +421,8 @@ void init_irq_proc(void)
 	/*
 	 * Create entries for all existing IRQs.
 	 */
-	for_each_irq_desc(irq, desc) {
-		if (!desc)
-			continue;
-
+	for_each_irq_desc(irq, desc)
 		register_irq_proc(irq, desc);
-	}
 }
 
 #ifdef CONFIG_GENERIC_IRQ_SHOW