ARM: dts: Cygnus: Fix PCIe controller interrupt type

Fix PCIe controller interrupt to use IRQ_TYPE_LEVEL_HIGH for Broadcom
Cygnus SoC

Fixes: cd590b50 ("ARM: dts: enable PCIe support for Cygnus")
Fixes: f6b88935

 ("ARM: dts: Enable MSI support for Broadcom Cygnus")
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>