ipq40xx: fix warning triggered by bad interrupt definition

ipq40xx: fix warning triggered by bad interrupt definition

This patch fixes a kernel warning that got triggered by 4.19
because of a bad/missing interrupt level definition in the DTS.

| WARNING: CPU: 2 PID: 1996 at drivers/irqchip/irq-gic.c:1016
| CPU: 2 PID: 1996 Comm: kmodloader Not tainted 4.19.9 #0
| Hardware name: Generic DT based system
| [<c0317884>] (warn_slowpath_null) from [<c04f9cd0>]
| [<c04f9cd0>] (gic_irq_domain_translate) from [<c035af30>]
| [<c035af30>] (irq_create_fwspec_mapping) from [<c035b1e0>]
| [<c035b1e0>] (irq_create_of_mapping) from [<c0614eec>]
| [<c0614eec>] (of_irq_get) from [<c0614f3c>]
| [<c0614f3c>] (of_irq_to_resource) from [<c0614ff0>]
| [<c0614ff0>] (of_irq_to_resource_table) from [<c0610e08>]
| [<c0610e08>] (of_device_alloc) from [<c0610ea0>]
| [<c0610ea0>] (of_platform_device_create_pdata)
| [<c061120c>] (of_platform_bus_create)
| [<c06113c4>] (of_platform_populate)
| [<bf4c06b4>] (dwc3_qcom_probe [dwc3_qcom])

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>