irqchip/mxs: Enable SKIP_SET_WAKE and MASK_ON_SUSPEND

The ICOLL controller doesn't provide any facility to configure the
wakeup sources. That's the reason why this implementation lacks
the irq_set_wake implementation. But this prevent us from properly
entering power management states like "suspend to idle".

So enable the flags IRQCHIP_SKIP_SET_WAKE and
IRQCHIP_MASK_ON_SUSPEND to let the irqchip core allows and handles
the power management.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Link: https://lkml.kernel.org/r/1482863397-11400-1-git-send-email-stefan.wahren@i2se.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>