gpio: zynq: Disable the irq if it is not a wakeup source

If gpio is not set to wake disable the interrupt. ATF set all slaves with
enabled interrupts as wakeup sources and if gpio is used in r5 then it
wakes up linux.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>