The GPIO expander is a interrupt-controller, so add the missing
 #interrupt-cells property as well.

Fixes: 71363a48 ("arm64: dts: freescale: add initial device tree for TQMa8Xx")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>