irqchip/bcm2836: Drop extra memory barrier in SMP boot.

The writel() immediately after this has a barrier, anyway.
Signed-off-by: NEric Anholt <eric@anholt.net>
Link: https://lkml.kernel.org/r/1454620468-31303-1-git-send-email-eric@anholt.netSigned-off-by: NJason Cooper <jason@lakedaemon.net>

drivers/irqchip/irq-bcm2836.c

@@ -229,7 +229,6 @@ int __init bcm2836_smp_boot_secondary(unsigned int cpu,
 	unsigned long secondary_startup_phys =
 		(unsigned long)virt_to_phys((void *)secondary_startup);
 
-	dsb();
 	writel(secondary_startup_phys,
 	       intc.base + LOCAL_MAILBOX3_SET0 + 16 * cpu);