irqchip/vic: Improve function-level documentation

The associated function, vic_init_cascaded, has never had a variable
irq_start.

Issue detected using Coccinelle (http://coccinelle.lip6.fr/)
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: kernel-janitors@vger.kernel.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1475351192-27079-14-git-send-email-Julia.Lawall@lip6.frSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-vic.c

@@ -498,7 +498,6 @@ void __init vic_init(void __iomem *base, unsigned int irq_start,
  * vic_init_cascaded() - initialise a cascaded vectored interrupt controller
  * @base: iomem base address
  * @parent_irq: the parent IRQ we're cascaded off
- * @irq_start: starting interrupt number, must be muliple of 32
  * @vic_sources: bitmask of interrupt sources to allow
  * @resume_sources: bitmask of interrupt sources to allow for resume
  *