ARM: shmobile: remove use of gic_arch_extn.irq_set_wake

ARM: shmobile: remove use of gic_arch_extn.irq_set_wake

shmobile only uses gic_arch_extn.irq_set_wake to prevent the GIC
from returning -ENXIO when receiving a wake-up configuration request.

It is a lot simpler to tell the irq layer that we don't need any
configuration by using the IRQCHIP_SKIP_SET_WAKE, thanks to the
new gic_set_irqchip_flags function.

Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1426088737-15817-3-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>