ARM: 7317/1: irq: avoid NULL check in for_each_irq_desc loop

ARM unconditionally selects CONFIG_GENERIC_HARDIRQS, so the definition
of for_each_irq_desc will check that the desc is non-NULL anyway.

This patch removes a redundant check from the IRQ migration code.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/irq.c

@@ -181,10 +181,7 @@ void migrate_irqs(void)
 	local_irq_save(flags);
 
 	for_each_irq_desc(i, desc) {
-		bool affinity_broken = false;
-
-		if (!desc)
-			continue;
+		bool affinity_broken;
 
 		raw_spin_lock(&desc->lock);
 		affinity_broken = migrate_one_irq(desc);