arm: zynq: Set proper GIC flags

Zynq is able to wake up on any IRQ, so flag it with
IRQCHIP_SKIP_SET_WAKE, and we want to mask off the IRQs when
going to suspend to avoid transient effects so also flag
this with IRQCHIP_MASK_ON_SUSPEND.

This is essentially, making the same changes as commit
'ARM: ux500: set proper GIC flags'
(sha1: 7e1f97ea) for Zynq.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>