arm64: dts: qcom: sc7180: Rename gic-its node to msi-controller

Running `make dtbs_check` yells:

  arch/arm64/boot/dts/qcom/sc7180-idp.dt.yaml: interrupt-controller@17a00000: gic-its@17a40000: False schema

From "arm,gic-v3.yaml" we can grok that this is explained by the
comment "msi-controller is preferred".  Switch to the preferred name
so that dtbs_check stops yelling.

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Fixes: 90db71e4 ("arm64: dts: sc7180: Add minimal dts/dtsi files for SC7180 soc")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20191212113540.2.Ibad7d3b0bea02957e89047942c61cc6c0aa61715@changeid


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>