genirq/irqdesc: Fix double increment in alloc_descs()

The recent rework of alloc_descs() introduced a double increment of the
loop counter. As a consequence only every second affinity mask is
validated.

Remove it.

[ tglx: Massaged changelog ]

Fixes: c410abbb ("genirq/affinity: Add is_managed to struct irq_affinity_desc")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Huacai Chen <chenhuacai@gmail.com>
Cc: Dou Liyang <douliyangs@gmail.com>
Link: https://lkml.kernel.org/r/1547694009-16261-1-git-send-email-chenhc@lemote.com

kernel/irq/irqdesc.c

@@ -457,7 +457,7 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node,
 
 	/* Validate affinity mask(s) */
 	if (affinity) {
-		for (i = 0; i < cnt; i++, i++) {
+		for (i = 0; i < cnt; i++) {
 			if (cpumask_empty(&affinity[i].mask))
 				return -EINVAL;
 		}