arm/dt: msm8226: Set IRQ ONESHOT flag

Irq ONESHOT flag is not active by being set in "interrupts"
dt setting.  It must be passed into request_threaded_irq,
so set appropriate flags in irq-gpio.

Change-Id: I3ea4a3d6612bad7fa1b3a1df88419f4dde5c884b
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>