irqchip: gic: Add support for cortex a7 compatible string

Patch 0a68214b "ARM: DT: Add binding for GIC virtualization extentions (VGIC)" added
the "arm,cortex-a7-gic" compatible string, but the corresponding IRQCHIP_DECLARE
was never added to the gic driver.

To let real Cortex-A7 SoCs use it, add the necessary declaration to the device driver.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lkml.kernel.org/r/1404388732-28890-1-git-send-email-matthias.bgg@gmail.com


Fixes: 0a68214b ("ARM: DT: Add binding for GIC virtualization extentions (VGIC)")
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Jason Cooper <jason@lakedaemon.net>