ARM: dts: qcom: ipq4019: Fix MSI IRQ type

The databook clearly states that the MSI IRQ (msi_ctrl_int) is a level
triggered interrupt.

The msi_ctrl_int will be high for as long as any MSI status bit is set,
thus the IRQ type should be set to IRQ_TYPE_LEVEL_HIGH, causing the
IRQ handler to keep getting called, as long as any MSI status bit is set.

A git grep shows that ipq4019 is the only SoC using snps,dw-pcie that has
configured this IRQ incorrectly.

Not having the correct IRQ type defined will cause us to lose interrupts,
which in turn causes timeouts in the PCIe endpoint drivers.

Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>