msm: copper: Add msm-gpio as an int-ctrl in Device Tree

All irq chip drivers must register with Device Tree. This allows
for translation of included interrupts, and irq_domain allocation
of the msm-gpio range on the system.

Change-Id: Ic587a810e28eac4b1216e885a22139681fe1c158
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>